Chapter 2 - Causes of Crop Loss in Canada

九年级英语精彩答案九年级英语精彩答案听力部分：第一节：1. What did the man do yesterday?答案：He watched a football match.2. Where did the woman go yesterday?答案：She went shopping.3. What sport does the man like best?答案：He likes basketball best.4. How did the woman feel about the traffic?答案：She felt it was terrible.5. What time does the man arrive at school?答案：At 7:45.第二节：6. Who is the girl talking to?答案：She is talking to her friend.7. What subject is the girl good at?答案：She is good at English.8. What did the boy buy for his sister?答案：He bought a book for her.9. What does the girl want to be when she grows up? 答案：She wants to be a fashion designer.10. What problem does the boy have?答案：He has trouble sleeping.听力材料：第一节：1. M: What did you do yesterday?W: I went shopping. How about you?M: I watched a football match.2. M: The traffic was terrible yesterday. Did you have any trouble? W: Yes, it was awful! I was stuck in it for nearly an hour.3. W: What sport do you like best?M: I like basketball best.4. M: How did you feel about the film?W: I think it was really good, but the ending was a bit confusing.5. W: What time do you arrive at school?M: I usually arrive at 7:45.第二节：6. W: Hi, Jane! Who are you talking to?M: Oh, I'm talking to my friend on the phone.7. W: What subject are you good at?M: I'm good at English.8. M: What did you buy for your sister's birthday?W: I bought her a book.9. W: What do you want to be when you grow up?M: I want to be a fashion designer.10. M: What's the matter? You look tired.W: I have trouble sleeping.阅读部分：A Life without ComputersA computer is a machine that we use almost every day. We can do many things with a computer. But what would life be like without computers?First of all, we wouldn't be able to use the Internet. We wouldn't be able tosend emails, play online games or do research on the web. We would have to rely on books and newspapers for information. Secondly, we wouldn't be able to use computers to do our work or study. We wouldn't be able to write essays or reports on the computer. We would have to write everything on paper.However, life would still go on. We would still be able to talk to friends and family in person. We would still be able to listen to music or watch television. We would just have to do things the old-fashioned way.So, maybe life without computers wouldn't be so bad after all!11. What is a computer?答案：A machine that we use almost every day.12. What wouldn't we be able to do without computers?答案：We wouldn't be able to use the Internet, send emails, do research on the web, or write essays or reports on the computer.13. What would we have to rely on for information without computers?答案：Books and newspapers.14. How would we write everything without computers?答案：We would have to write everything on paper.15. Would life still go on without computers?答案：Yes, life would still go on.BMy HobbiesI have many hobbies that I enjoy doing in my free time. One of my favorite hobbies is playing basketball. I play basketball every weekend with my friends. We have a lot of fun and it's a great way to get exercise.Another hobby of mine is reading. I love to read all kinds of books, but my favorite type of book is science fiction. I can spend hours reading a good science fiction book.I also like to travel. I have been to many countries around the world and I hope to visit even more. It's a great way to experience different cultures and to learn about the world.In addition, I enjoy playing video games. I play video games with my brother and we have a lot of fun. It's a great way to relax and unwind after a long day.16. What is one of the writer's favorite hobbies?答案：Playing basketball.17. Who does the writer play basketball with?答案：The writer plays basketball with friends.18. What is the writer's favorite type of book?答案：Science fiction.19. How long can the writer spend reading a good science fiction book?答案：The writer can spend hours reading a good science fiction book. 20. Who does the writer play video games with?答案：The writer plays video games with their brother.完形填空部分：What is climate change?Climate change is a long-term shift in global or _______ climate patterns. Itaffects the Earth's temperature, rainfall, winds, and other features. It is caused primarily by human activities, such as burning fossil fuels, which releases greenhouse gases into the atmosphere. These gases trap heat from the sun and cause the Earth's temperature to rise.The effects of climate change can be _______ to people and the environment. They include rising sea levels, extreme weather events, decreased crop yields, and melting polar ice caps. These changes can lead to food and water shortages, the spread of disease, and the loss of _______species.There are steps that can be taken to _______the effects of climate change. These include using renewable energy sources, reducing waste and pollution, and conserving energy. Governments and individuals can work together to reduce greenhouse gas emissions and protect the planet.Climate change is a serious issue that affects us all. We must take action to mitigate its effects and protect our planet for future generations.21. What is climate change?答案：A long-term shift in global or regional climate patterns.22. What causes climate change?答案：Human activities, such as burning fossil fuels, which releases greenhouse gases into the atmosphere.23. What are the effects of climate change?答案：Rising sea levels, extreme weather events, decreased crop yields, and melting polar ice caps. These changes can lead to food and water shortages, the spread of disease, and the loss of species.24. What steps can be taken to mitigate the effects of climate change?答案：Using renewable energy sources, reducing waste and pollution, and conserving energy.25. Who can work together to reduce greenhouse gas emissions and protect the planet?答案：Governments and individuals.。

2021年全国硕士研究生招生考试英语（二）试题Section I Use of EnglishDirections:Read the following text. Choose the best word(s) for each numbered blank and mark [A], [B], [C]or [D] on the ANSWER SHEET. (10 points)It’s not difficult to set targets for staff. It is much harder, 1 , to understand their negative consequences. Most work-related behaviors have multiple components. 2 one and the others become distorted.Travel on a London bus and you’ll 3 see how this works with drivers. Watch people get on and show their tickets. Are they carefully inspected? Never. Do people get on without paying? Of course! Are there inspectors to 4 that people have paid? Possibly, but very few. And people who run for the bus? They are 5 . How about jumping lights? Buses do so almost as frequently as cyclists.Why? Because the target is 6 . People complained that buses were late and infrequent.7 , the number of buses and bus lanes were increased, and drivers were8 or punished according to the time they took. And drivers hit these targets. But they 9 hit cyclists. If the target was changed to 10 , you would have more inspectors and more sensitive pricing. If the criterion changed to safety, you would get more 11 drivers who obeyed traffic laws. But both these criteria would be at the expense of time.There is another 12 : people became immensely inventive in hitting targets. Have you13 that you can leave on a flight an hour late but still arrive on time? Tailwinds? Of course not! Airlines have simply changed the time a 14 is meant to take. A one-hour flight is now billed as a two-hour flight.The15 of the story is simple. Most jobs are multidimensional, with multiple criteria. Choose one criterion and you may well 16 others. Everything can be done faster and made cheaper, but there is a17 . Setting targets can and does have unforeseen negative consequences.This is not an argument against target-setting. But it is an argument for exploring consequences first. All good targets should have multiple criteria 18 critical factors such as time, money, quality and customer feedback. The trick is not only to 19 just one or even two dimensions of the objective, but also to understand how to help people better 20 the objective.1. [A] therefore[B] however[C] again[D]moreover2. [A] Emphasize[B] Identify[C] Access[D] Explain3. [A] nearly[B] curiously[C] eagerly[D] quickly4. [A] claim[B] prove[C] check[D]recall5. [A] ignored[B] threatened[C] mocked[D] blamed6. [A] punctuality[B] hospitality[C] competition[D] innovation7. [A] Yet[B] So[C] Besides[D] Still8. [A] hired[B] trained[C] rewarded[D] grouped9. [A] only[B] rather[C] once[D] also10. [A] comfort[B] revenue[C] efficiency[D] security11. [A] friendly[B] quiet[C] cautious[D] diligent12. [A]purpose[B] problem[C] prejudice[D] policy13. [A] reported[B] revealed[C] admitted[D] noticed14. [A] break[B] trip[C] department[D] transfer15. [A] moral[B] background[C] style[D] form16. [A] interpret[B] criticize[C] sacrifice[D] tolerate17. [A] task[B] secret[C] protect[D] cost18. [A] leading to[B] calling for[C] relating to[D] accounting for19. [A] specify[B] predict[C] restore[D] create20. [A] modify[B] review[C] present[D] achieveSection II Reading ComprehensionPart ADirections:Read the following four texts. Answer the questions after each text by choosing [A], [B], [C] or [D]. Mark your answers on the ANSWER SHEET. (40 points)Text 1“Reskilling” is something that sounds like a buzzword but is actually a requirement if we plan to have a future where a lot of would-be workers do not get left behind. We know we are moving into a period where the jobs in demand will change rapidly, as will the requirements of the jobs that remain. Research by WEF detailed in the Harvard Business Review, finds that on average 42 per cent of the “core skills” within job roles will change by 2022. That is a very short timeline, so we can only imagine what the changes will be further in the future.The question of who should pay for reskilling is a thorny one. For individual companies, the temptation is always to let go of workers whose skills are no longer in demand and replace them with those whose skills are. That does not always happen. AT&T is often given as the gold standard of a company who decided to do a massive reskilling program rather than go with a fire-and-hire strategy, ultimately retraining 18,000 employers. Prepandemic, other companies including Amazon and Disney had also pledged to create their own plans. When the skills mismatch is in the broader economy though, the focus usually turns to government to handle. Efforts in Canada and elsewhere have been arguably languid at best, and have given us a situation where we frequently hear of employers begging for workers, even at times and in regions where unemployment is high.With the pandemic, unemployment is very high indeed. In February, at 3.5 per cent and 5.5 per cent respectively, unemployment rates in Canada and the United States were at generational lows and worker shortages were everywhere. As of May, those rates had spiked up to 13.3 per cent and 13.7 per cent, and although many worker shortages had disappeared, not all had done so. In the medical filed, to take an obvious example, the pandemic meant that there were still clear shortages of doctors, nurses and other medical personnel.Of course, it is not like you can take an unemployed waiter and train him to be a doctor in a few weeks, no matter who pays for it. But even if you cannot close that gap, maybe you can close others, and doing so would be to the benefit of all concerned. That seems to be the case in Sweden: when forced to furlough 90 per cent of their cabin staff, Scandinavian Airlines decided to start up a short retraining program that reskilled the laid-off workers to support hospital staff. The effort was a collective one and involved other companies as well as a Swedish university.21.Research by the World Economic Forum suggests .[A]a controversy about the “core skills”[B]an increase in full-time employment[C]an urgent demand for new job skills[D]a steady growth of job opportunities22.AT&T is cited to show .[A]an immediate need for government support[B]an alternative to the fire-and-hire strategy[C]the characteristics of reskilling programs[D]the importance of staff appraisal standards23.Efforts to resolve the skills mismatch in Canada .[A]have appeared to be insufficient[B]have driven up labour costs[C]have proved to be inconsistent[D]have met with fierce opposition24.We can learn from Paragraph 3 that there was .[A]a sign of economic recovery[B]a call for policy adjustment[C]a change on hiring practices[D]a lack of medical workers25.Scandinavian Airlines decided to .[A]create job vacancies for the unemployed[B]retrain their cabin staff for better services[C]prepare their laid-off workers for other jobs[D]finance their staff’s college educationText 2With the global population predicted to hit close to 10 billion by 2050, and forecasts that agricultural production in some regions will need to nearly double to keep pace, food security is increasingly making headlines. In the UK, it has become a big talking point recently too, for a rather particular reason: Brexit.Brexit is seen by some as an opportunity to reverse a recent trend towards the UK importing food. The country produces only about 60 per cent of the food it eats, down from almost three-quarters in the late 1980s. A move back to self-sufficiency, the argument goes, would boost the farming industry, political sovereignty and even the nation’s health. Sounds great –but how feasible is this vision?According to a report on UK food production from the University of Leeds, UK, 85 per cent of the country’s total land area is associated with meat and dairy production. That supplies 80 per cent of what is consumed, so even covering the whole country in livestock farms wouldn’t allow us to cover all our meat and dairy needs.There are many caveats to those figures, but they are still grave. To become much more self-sufficient, the UK would need to drastically reduce its consumption of animal foods, and probably also farm more intensively – meaning fewer green fields, and more factory-style production.But switching to a mainly plant-based diet wouldn’t help. There is a good reason why the UK is dominated by animal husbandry: most of its terrain doesn’t have the right soil or climate to grow crops on a commercial basis. Just 25 per cent of the country’s land is suitab le for crop-growing, most of which is already occupied by arable fields. Even if we converted all the suitable land to fields of fruit and veg –which would involve taking out all the nature reserves and removing thousands of people from their homes – we would achieve only a 30 per cent boost in crop production.Just 23 per cent of the fruit and vegetables consumed in the UK are currently home-grown, so even with the most extreme measures we could meet only 30 per cent of our fresh produce needs. That is before we look for the space to grow the grains, sugars, seeds and oils that provide us with the vast bulk of our current calorie intake.26.Some people argue that food self-sufficiency in the UK would .[A]be hindered by its population growth[B]contribute to the nation's well-being[C]become a priority of the government[D]pose a challenge to its farming industry27.The report by the University of Leeds shows that in the UK .[A]farmland has been inefficiently utilized[B]factory-style production needs reforming[C]most land is used for meat and dairy production[D]more green fields will be converted for farming28.Crop-growing in the UK is restricted due to .[A]its farming technology[B]its dietary tradition[C]its natural conditions[D]its commercial interests29.It can be learned from the last paragraph that British people .[A]rely largely on imports for fresh produce[B]enjoy a steady rise in fruit consumption[C]are seeking effective ways to cut calorie intake[D]are trying to grow new varieties of grains30.The author's attitude to food self-sufficiency in the UK is .[A]defensive[B]doubtful[C]tolerant[D]optimisticText 3When Microsoft bought task management app Wunderlist and mobile calendar Sunrise in 2015. It picked up two newcomers that were attracting considerable buzz in Silicon Valley. Microsoft’s own Office dominates the market for “productivity” software, but the start-ups represented a new wave of technology designed from the ground up for the smartphone world.Both apps, however, were later scrapped, after Microsoft said it had used their best features in its own products. Their teams of engineers stayed on, mak ing them two of the many “acqui-hires” that the biggest companies have used to feed their insatiable hunger for tech-talent.To Microsoft’s critics, the fates of Wunderlist and Sunrise are examples of a remorseless drive by Big Tech to chew up any innovati ve companies that lie in their path. “They bought the seedlings and closed them down,” complained Paul Arnold, a partner at San Francisco-based Switch Ventures, putting paid to businesses that might one day turn into competitors. Microsoft declined to comment.Like other start-up investors. Mr. Arnold’s own business often depends on selling start-ups to larger tech companies, though he admits to mixed feelings about the result: “I think these things are good for me, if I put my selfish hat on. But are they good for the American economy? I don't know.”The US Federal Trade Commission says it wants to find the answer to that question. This week, it asked the five most valuable US tech companies for information about their many small acquisitions over the past decade. Although only a research project at this stage, the request has raised the prospect of regulators wading into early-stage tech markets that until now have been beyond their reach.Given their combined market value of more than $5.5tn, rifling through such small deals—many of them much less prominent than Wunderlist and Sunrise—might seem beside the point. Between them, the five companies (Apple, Microsoft, Google, Amazon and Facebook) have spent an average of only $3.4bn a year on sub-$1bn acquisitions over the past five years—a drop in the ocean compared with their massive financial reserves, and the more than $130bn of venture capital that was invested in the US last year.However, critics say that the big companies use such deals to buy their most threatening potential competitors before their businesses have a chance to gain momentum, in some cases as part of a “buy and kill” tactic to simply close them down.31.What is true about Wunderlist and Sunrise after their acquisitions?[A]Their engineers were retained.[B]Their market values declined.[C]Their tech features improved.[D]Their products were re-priced.32.Microsoft’s critics believe that the big tech companies tend to .[A]exaggerate their product quality[B]eliminate their potential competitors[C]treat new tech talent unfairly[D]ignore public opinions33.Paul Arnold is concerned that small acquisitions might .[A]weaken big tech companies[B]worsen market competition[C]harm the national economy[D]discourage start-up investors34.The US Federal Trade Commission intends to .[A]limit Big Tech’s expansion[B]encourage research collaboration[C]examine small acquisitions[D]supervise start-ups’ operations35.For the five biggest tech companies, their small acquisitions have .[A]brought little financial pressure[B]raised few management challenges[C]set an example for future deals[D]generated considerable profitsText 4We’re fairly good at judging people based on first impressions, thin slices of experience ranging from a glimpse of a photo to a five-minute interaction, and deliberation can be not only extraneous but intrusive. In one study of the ability she dubbed “thin slicing,” the late psychologist Nalini Ambady asked participants to watch silent 10-second video clips of professors and to rate the instructor’s overall effectiveness. Their ratings correlated strongly with students’ end-of-semester ratings. Another set of participants had to count backward from 1,000 by nines as they watched the clips, occupying their conscious working memory. Their ratings were just as accurate, demonstrating the intuitive nature of the social processing.Critically, another group was asked to spend a minute writing down reasons for their judgment, before giving the rating. Accuracy dropped dramatically. Ambady suspected thatdeliberation focused them on vivid but misleading cues, such as certain gestures or utterances, rather than letting the complex interplay of subtle signals form a holistic impression. She found similar interference when participants watched 15-second clips of pairs of people and judged whether they were strangers, friends, or dating partners.Other res earch shows we’re better at detecting deception and sexual orientation from thin slices when we rely on intuition instead of reflection. “It’s as if you’re driving a stick shift,” says Judith Hall, a psychologist at Northeastern University, “and if you sta rt thinking about it too much, you can’t remember what you’re doing. But if you go on automatic pilot, you’re fine. Much of our social life is like that.”Thinking too much can also harm our ability to form preferences. College students’ ratings of strawbe rry jams and college courses aligned better with experts’ opinions when the students weren’t asked to analyze their rationale. And people made car-buying decisions that were both objectively better and more personally satisfying when asked to focus on their feelings rather than on details, but only if the decision was complex—when they had a lot of information to process.Intuition’s special powers are unleashed only in certain circumstances. In one study, participants completed a battery of eight tasks, including four that tapped reflective thinking (discerning rules, comprehending vocabulary) and four that tapped intuition and creativity (generating new products or figures of speech). Then they rated the degree to which they had used intuition (“gut feelings,” “hunches,” “my heart”). Use of their gut hurt their performance on the first four tasks, as expected, and helped them on the rest. Sometimes the heart is smarter than the head.36.Nalini Ambady’s study deals with .[A] the power of people’s memory[B] the reliability of first impressions[C] instructor student interaction[D] people’s ability to influence others37.In Ambady’s study, rating accuracy dropped when participants .[A] focused on specific details[B] gave the rating in limited time[C] watched shorter video clips[D] discussed with one another38.Judith Hall mentions driving to show that .[A] reflection can be distracting[B] memory can be selective[C] social skills must be cultivated[D] deception is difficult to detect39.When you are making complex decisions, it is advisable to .[A] collect enough data[B] list your preferences[C] seek expert advice[D] follow your feelings40.What can we learn from the last paragraph?[A] Generating new products takes time.[B] Intuition may affect reflective tasks.[C] Vocabulary comprehension needs creativity.[D] Objective thinking may boost inventiveness.Part BDirections:Read the following text and answer the questions by choosing the most suitable subheading from the list A-G for each of the numbered paragraphs (41-45). There are two extra subheadings. Mark your answers on the ANSWER SHEET. (10 points)A.Stay calmB.Stay humbleC.Be realistic about the risksD.Identify a shared goalE.Decide whether to waitF.Ask permission to disagreeG.Don't make judgmentsHow to Disagree with Someone More Powerful than You Your boss proposes a new initiative you think won’t work. Your senior colleague outlines a project timeline you think is unrealistic. What do you say when you disagree with someone who has more power than you do? How do you decide whether it’s worth speaki ng up? And if you do, what exactly should you say?41.You may decide it’s best to hold off on voicing your opinion. Maybe “you haven’t finished thinking the problem through, the whole discussion was a surprise to you, or you want to get a clearer sense of what the group thinks,” says Weeks. “If you think othe r people are going to disagree too, you might want to gather your army first. People can contribute experience or information to your thinking—all the things that would make the disagreement stronger or more valid.” It’s also a good idea to delay the conversation if you’re in a meeting or other public space. Discussing the issue in private will make the powerful person feel less threatened.42.Before you share your thoughts, think about what the powerful person cares about—it may be “the credibility of their team or getting a project done on time,” says Grenny. You’re more likely to be heard if you can connect your disagreement to a “higher purpose.” When you do speak up, don’t assume the link will be clear. You’ll want to state it overtly, contextualizi ng your statements so that you’re seen not as a disagreeable underling but as a colleague who’s trying to advance a shared goal. The discussion will then become “more like a chess game than a boxing match,” says Weeks.43.This step may sound overly de ferential, but, according to Grenny, it’s a smart way to give the powerful person “psychological safety” and control. You can say something like, “I know we seem to be moving toward a first-quarter commitment here. I have reasons to think that won’t work. I’d like to lay out my reasoning. Would that be OK?” This gives the person a choice, “allowing them to verbally opt in,” says Grenny. And, assuming they say yes, it will make you feel more confident about voicing your disagreement.44.You might feel your heart racing or your face turning red, but do whatever you can to remain neutral in both your words and actions. When your body language communicates reluctance or anxiety, it undercuts the message, Weeks says. It sends “a mixed message, and your counterpart gets to choose what to read,” she explains. Deep breaths can help, as can speaking more slowly and deliberately. “When we feel panicky we tend to talk louder and faster. You don’t want to be mousey or talk in a whisper, but simply slowing the pace and talking in an even tone helps calm the other person down and does the same for you,” says Grenny. It also makes you seem confident, even if you aren’t.45.Emphasize that you’re offering your opinion, not “gospel truth,” says Grenny. “It may be a well-informed, well-researched opinion, but it’s still an opinion, so talk tentatively and slightly understate your confidence.” Instead of saying something like, “If we set an end-of-quarter deadline, we’ll never make it,” say, “This is just my opinion, but I don’t see how we will make that deadline.” Weeks suggests adding a lot of “guiding phrases” like “I’m thinking aloud here.” This will leave room for dialogue. Having asserted your position (as a position, not as a fact), “demonstrate equal curiosity about other views,” says Grenny. Remind the person that this is your point of view, and then invite critique. Weeks suggests trying something like, “Tell me where I’m wrong with this.” Be genuinely open to hearing other opinions.”Section III Translation46.Directions:Translate the following text into Chinese. Write your translation on the ANSWER SHEET. (15 points)We tend to think that friends and family members are our biggest sources of connection, laughter, and warmth. While that may well be true, researchers have also recently found that interacting with strangers actually brings a boost in mood and feelings of belonging that we didn't expect.In one series of studies, researchers instructed Chicago-area commuters using public transportation to strike up a conversation with someone near them. On average, participants who followed this instruction felt better than those who had been told to stand or sit in silence. The researchers also argued that when we shy away from casual interactions with strangers, it is often due to a misplaced anxiety that they might not want to talk to us. Much of the time, however, this belief is false. As it turns out, many people are actually perfectly willing to talk—and may even be flattered to receive your attention.Section ⅣWritingPart A47.Directions：Suppose you are organizing an online meeting. Write an email to Jack, an international student, to1)invite him to participate, and2)tell him the details.You should write about 100 words on the ANSWER SHEET.Do not use your own name. Use “Li Ming” instead.Do not write your address. (10 points)Part B48.Directions：Write an essay based on the chart below. In your writing, you should1)interpret the chart, and2)give your comments.You should write about 150 words on the ANSWER SHEET. (15 points)2021年答案速查表Section I Use of English (10 points)1. B2. A3. D4. C5. A6. A7. B8. C9. D 10. B11. C 12. B 13. D 14. B 15. A 16. C 17. D 18. C 19. A 20. DSection II Reading Comprehension (50 points)Part A (40 points)Text 1 21. C 22. B 23. A 24. D 25. CText 2 26. B 27. C 28. C 29. A 30. BText 3 31. A 32. B 33. C 34. C 35. AText 4 36. B 37. A 38. A 39. D 40. BPart B (10 points)41. E 42. D 43. F 44. A 45. BSection III (15 points)我们通常认为，情感、欢笑和温暖最主要的来源是朋友及家人。

Habitat destruction
abstract
1.
What is the habitat destruction. 2. What results in the habitat destruction. 3. The examples of habitat destruction. 4. The effects of habitat destruction.
introduction
Definition:
Habitat
destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity.
Human destroyed the forests ，the home of wild animals，in order to develop urbanization or convert forest land to row-crop agriculture.
Impact
Impact：
1. 2.
causes
Natural causes
climate changes
volcanism
causes
Slash and burn
刀耕火种
Human causes
Deforestation
开荒毁林
Example:

drought 英语介绍What is Drought?Drought is a prolonged period of abnormally dry weather, resulting in a shortage of water supply for various uses such as irrigation, household consumption, and industrial processes. It is a natural disaster that can have severe impacts on ecosystems, agriculture, economies, and human lives. Droughts can occur in any climate zone and can range in duration, severity, and geographic extent. In this article, we will delve deeper into the causes, effects, and strategies for mitigating the impacts of drought.Causes of DroughtSeveral factors contribute to the onset of drought, including natural variability in climate patterns and anthropogenic activities. Natural causes of drought include weather patterns like El Niño and La Niña, which can disrupt rainfall patterns and lead to prolonged dry periods. Climate change also plays a role in increasing the frequency and intensity of droughts, altering precipitation patterns and exacerbating water scarcity in certain regions.Human activities can also contribute to the occurrence of drought. Deforestation, for instance, reduces the capacity of forests to retain water, leading to decreased water availability in adjacent areas. Additionally, excessive water consumption by agriculture and industrial sectors can deplete water sources, exacerbating drought conditions. Poor water management practices, such as inefficient irrigation methods and inadequate water storage infrastructure, can further amplify the impacts of drought.Effects of DroughtDrought can have extensive impacts on various sectors and ecosystems. The agricultural sector is particularly susceptible, as crops and livestock depend heavily on water for growth and sustenance. Droughts can lead to crop failures, reduced agricultural yields, and livestock deaths, causing food shortages and price hikes. In addition to the immediate economic consequences, the longterm effects of drought on agriculture can include soil degradation, reduced soil fertility, and loss of vegetation cover.Ecosystems also suffer during droughts, with decreased water availability disrupting natural processes and habitats. Rivers, lakes, and groundwaterreservoirs can dry up, threatening the survival of aquatic species and diminishing biodiversity. Forests become vulnerable to wildfires, as dry vegetation becomes highly flammable. Moreover, droughts can lead to ecological imbalances, such as invasive species proliferation, which can further harm native flora and fauna.Droughts also impact human lives and economies. Water scarcity affects human health and hygiene, with a higher risk of waterborne diseases. Indigenous communities and disadvantaged populations are particularly vulnerable, as they often lack access to alternative water sources or means to cope with the impacts of drought. Economic sectors such as energy production, manufacturing, and tourism can also suffer as water scarcity hampers operations, increases costs, and decreases productivity.Mitigation and Adaptation StrategiesTo mitigate the impacts of drought, a combination of preventive measures, water management strategies, and adaptive practices are necessary. Integrated water resources management (IWRM) plays a crucial role in drought mitigation by balancing water supply and demand. This involves improving water efficiency, implementing water conservation practices, and promoting sustainable water use across sectors.Investing in water storage infrastructure, such as dams and reservoirs, increases water availability during dry periods. Implementing watersaving technologies and encouraging practices like rainwater harvesting and wastewater reuse also contribute to mitigating the impacts of drought. Moreover, enhancing soil conservation practices, such as afforestation and conservation agriculture, can improve soil moisture retention and reduce the effects of drought on agriculture.In terms of adaptive measures, enhancing early warning systems, drought monitoring, and forecasting can enable timely preparedness and response actions. Government agencies, in collaboration with local communities, should develop drought contingency plans that outline water allocation priorities, emergency response measures, and alternative water sources. Diversifying water sources through investment in desalination plants, interbasin water transfers, and water recycling can help alleviate the impacts of drought.Building resilience to drought also requires raising awareness and educating the public about water conservation practices and sustainable water use. Encouraging behavioral changes and promoting watersaving habits at home, schools, and workplaces can contribute to longterm watersecurity. Additionally, supporting research and innovation in waterrelated technologies and practices can lead to more efficient and sustainable solutions for drought management.ConclusionDrought is a complex phenomenon that poses significant challenges to ecosystems, economies, and human wellbeing. Addressing the causes and impacts of drought requires a multidimensional approach that involves climate change mitigation, water management strategies, and adaptive measures. By implementing comprehensive and integrated solutions, societies can build resilience and ensure water security in the face of future drought events.。

描述天气现象英语作文全文共3篇示例，供读者参考篇1Weather phenomena are a fascinating aspect of nature that have always captivated humans. From the serene beauty of a clear blue sky to the awe-inspiring power of a violent thunderstorm, the weather constantly surrounds us and impacts our daily lives. In this essay, I will describe some of the most common weather phenomena and the ways in which they affect the world around us.One of the most common weather phenomena is rain. Rain occurs when water vapor in the atmosphere condenses into droplets that fall to the ground. Rain is essential for sustaining life on Earth, as it provides the necessary moisture for plants to grow and thrive. However, excessive rainfall can lead to flooding and other hazards, while prolonged droughts can cause crop failures and water shortages.Another common weather phenomenon is wind. Wind is simply the movement of air from an area of high pressure to an area of low pressure. Wind can range from a gentle breeze to apowerful gale, and it plays a crucial role in shaping the Earth's climate and weather patterns. Wind can also carry pollutants and allergens, making it an important factor in air quality and human health.Thunderstorms are another fascinating weather phenomenon. Thunderstorms occur when warm, moist air rises rapidly in the atmosphere, creating unstable conditions that lead to the formation of cumulonimbus clouds. These towering clouds can produce lightning, thunder, heavy rain, and even hail. Thunderstorms are a common occurrence in many parts of the world and can be both beautiful and dangerous.Snow and ice are two more weather phenomena that are particularly prevalent in colder regions. Snow forms when water vapor in the atmosphere freezes into ice crystals, which then fall to the ground as snowflakes. Snow can create stunning winter landscapes, but it can also cause transportation disruptions and pose hazards to people and animals. Ice is another form of precipitation that occurs when rain freezes upon contact with a cold surface, creating icy conditions that can be treacherous to navigate.Fog is a weather phenomenon that occurs when the air near the ground becomes saturated with moisture, leading toreduced visibility. Fog can form in a variety of conditions, including when warm air moves over a cold surface or when cool air settles into low-lying areas. Fog can make driving and flying hazardous, as it can obscure road signs and runway lights, making it difficult to see ahead.Tornadoes and hurricanes are some of the most powerful and destructive weather phenomena on Earth. Tornadoes are violent, rotating columns of air that form within severe thunderstorms and can cause widespread damage in a matter of minutes. Hurricanes are large, swirling storms that form over warm ocean waters and can bring high winds, heavy rain, and flooding to coastal areas. Both tornadoes and hurricanes are capable of causing devastation and loss of life, making them some of the most feared weather phenomena in the world.In conclusion, weather phenomena are an integral part of our natural environment and play a crucial role in shaping the world around us. From the gentle caress of a summer breeze to the raw power of a hurricane, weather phenomena are a constant reminder of the beauty and unpredictability of nature. By observing and understanding these phenomena, we can better prepare for and adapt to the ever-changing conditions of the world we inhabit.篇2Weather is a fascinating aspect of our environment that can greatly impact our daily lives. From sunny days to stormy nights, the weather can change rapidly and drastically. In this essay, we will explore different weather phenomena and how they affect us.One of the most common weather phenomena is rain. Rain occurs when water vapor in the atmosphere condenses and falls to the ground as precipitation. Rain can be a gentle drizzle or a heavy downpour, and it can last for minutes or days. Rain is essential for plants, animals, and humans to survive, as it provides much-needed moisture for growth and hydration.Another common weather phenomenon is wind. Wind is created by the uneven heating of the Earth's surface, which causes air to move from high-pressure areas to low-pressure areas. Wind can be a gentle breeze or a powerful gust, and it can carry dust, pollen, and other particles with it. Wind is also responsible for shaping the Earth's surface through processes like erosion and deposition.Thunderstorms are a more intense weather phenomenon that can bring heavy rain, strong winds, lightning, and thunder.Thunderstorms occur when warm, moist air rises and cools, forming cumulonimbus clouds. Lightning is created by the discharge of electricity between the positively charged top of a cloud and the negatively charged ground. Thunder is the sound produced by the rapid expansion and contraction of air heated by lightning.Tornadoes are one of the most destructive weather phenomena, with powerful winds that can reach speeds of over 200 mph. Tornadoes form when warm, moist air collides with cold, dry air, creating a rotating updraft. The spinning air tightens into a funnel cloud, which can touch down as a tornado. Tornadoes can destroy buildings, uproot trees, and cause significant damage in a matter of minutes.Blizzards are another dangerous weather phenomenon, characterized by heavy snowfall, high winds, and cold temperatures. Blizzards occur when warm air from the Gulf of Mexico clashes with cold air from Canada, creating intense snowstorms. Blizzards can create whiteout conditions, where visibility is reduced to near zero, making travel dangerous and difficult.In conclusion, weather phenomena are an integral part of our natural world, shaping our environment and influencing ourdaily lives. From rain and wind to thunderstorms and tornadoes, each weather phenomenon has its own unique characteristics and impacts. By understanding and respecting these phenomena, we can better prepare for and adapt to the ever-changing weather around us.篇3Weather is a fascinating topic that affects all of us on a daily basis. From sunny skies to thunderstorms, each type of weather phenomenon has its own unique characteristics and impact on our lives. In this essay, we will explore some of the most common weather phenomena and how they shape our world.One of the most common weather phenomena is rain. Rain occurs when water vapor in the atmosphere condenses into droplets and falls to the ground. Rain can vary in intensity, from a light drizzle to a heavy downpour. It is important for the health of plants and animals, as it provides much-needed water for growth and hydration. However, excessive rain can lead to flooding and damage to property.Another common weather phenomenon is wind. Wind is caused by the movement of air from areas of high pressure to areas of low pressure. It can be gentle and refreshing, or strongand destructive. Wind is important for dispersing seeds, pollinating plants, and generating power through wind turbines. However, strong winds can also cause damage by toppling trees, blowing down power lines, and creating dangerous conditions for outdoor activities.Snow is another fascinating weather phenomenon, especially for those who live in colder climates. Snow forms when water vapor in the atmosphere freezes into ice crystals, which then fall to the ground as snowflakes. Snow can create a beautiful winter wonderland, but it can also cause transportation delays, school closures, and power outages. Snow is important for insulating the ground, providing moisture for plants, and replenishing freshwater supplies.One of the most awe-inspiring weather phenomena is the rainbow. Rainbows occur when sunlight is refracted, or bent, by water droplets in the atmosphere. This creates a spectrum of colors that arcs across the sky. Rainbows are a symbol of hope and beauty, and they are often seen as a sign of good luck. People have marveled at rainbows for centuries, and they continue to inspire wonder and joy in our modern world.Thunderstorms are another powerful weather phenomenon that can be both exciting and dangerous. Thunderstorms formwhen warm, moist air rises and cools, creating towering cumulonimbus clouds. Lightning, thunder, heavy rain, and strong winds are common features of thunderstorms. While thunderstorms can be beautiful to watch from a distance, they can also bring havoc in the form of downed trees, hail, flash floods, and tornadoes. It is important to take shelter during a thunderstorm and stay safe until the storm has passed.In conclusion, weather phenomena are an integral part of our lives and our planet. From rain and wind to snow and rainbows, each type of weather phenomenon has its own unique characteristics and impact on our world. By learning more about these phenomena and how they form, we can better understand and appreciate the wonders of the natural world. Next time you step outside and feel the sun on your face, or watch a rainbow arc across the sky, take a moment to marvel at the beauty and power of the weather around you.。

自然灾害英语作文思维导图Natural disasters are unpredictable events that can have devastating consequences on human lives, infrastructure, and the environment. These catastrophic occurrences are often the result of complex interactions between various natural phenomena and human activities. Understanding the causes, effects, and mitigation strategies of natural disasters is crucial in order to minimize their impact and ensure the safety and well-being of communities around the world.One of the most common and destructive natural disasters is the earthquake. Earthquakes are sudden and violent shaking of the Earth's surface caused by the movement of tectonic plates beneath the Earth's crust. They can range in magnitude from minor tremors to powerful quakes that can level entire cities. Earthquakes can trigger other natural disasters such as tsunamis, landslides, and fires, further exacerbating the damage and loss of life. Effective earthquake preparedness measures include building infrastructure that can withstand seismic activity, implementing early warning systems, and educating the public on emergency responseprocedures.Floods are another prevalent natural disaster that can have devastating consequences. Floods can be caused by heavy rainfall, rapid snowmelt, dam failures, or coastal storm surges. They can lead to the destruction of homes, businesses, and critical infrastructure, as well as the contamination of water supplies and the spread of waterborne diseases. Flood mitigation strategies include constructing flood-resistant buildings, implementing drainage systems, and developing early warning and evacuation plans.Hurricanes, also known as typhoons or cyclones, are powerful tropical storms characterized by intense winds, heavy rainfall, and storm surges. These natural disasters can cause widespread damage to coastal regions, including the destruction of homes, businesses, and infrastructure, as well as the displacement of thousands of people. Effective hurricane preparedness measures include strengthening building codes, improving emergency response systems, and educating the public on evacuation procedures.Wildfires are another type of natural disaster that can have far-reaching consequences. These uncontrolled, rapidly spreading fires can be sparked by lightning, human activity, or even spontaneous combustion. Wildfires can destroy vast swaths of forests, grasslands, and even urban areas, leading to the loss of human lives, thedestruction of property, and the disruption of ecosystems. Strategies to mitigate the impact of wildfires include implementing fire-resistant building materials, creating defensible spaces around homes, and conducting controlled burns to reduce fuel loads.Volcanic eruptions are another natural disaster that can have catastrophic effects. Volcanoes are openings in the Earth's surface that allow molten rock, gases, and other materials to escape from the planet's interior. Volcanic eruptions can produce a range of hazards, including lava flows, ash clouds, and pyroclastic flows, which can devastate surrounding areas and disrupt global air travel. Effective volcano monitoring and early warning systems, as well as the development of evacuation plans, are crucial in mitigating the impact of these natural disasters.In addition to these well-known natural disasters, there are also other types of natural events that can have significant consequences, such as drought, heatwaves, and severe storms. Drought, for example, can lead to water scarcity, crop failure, and the degradation of ecosystems, while heatwaves can cause heat-related illnesses and deaths, as well as strain on critical infrastructure. Severe storms, such as tornadoes, thunderstorms, and blizzards, can also cause widespread damage and disruption to communities.Regardless of the type of natural disaster, the impact on human livesand the environment can be profound. Natural disasters can lead to the loss of human life, the destruction of homes and businesses, the disruption of essential services, and the degradation of natural ecosystems. Moreover, the effects of natural disasters can be long-lasting, with communities often struggling to recover and rebuild in the aftermath.To mitigate the impact of natural disasters, a comprehensive approach is necessary. This includes improving early warning systems, strengthening infrastructure, enhancing emergency response capabilities, and promoting public awareness and education. Additionally, efforts to address the underlying causes of natural disasters, such as climate change and environmental degradation, are crucial in building more resilient and sustainable communities.In conclusion, natural disasters are complex and multifaceted phenomena that require a holistic understanding and a coordinated response. By understanding the causes, effects, and mitigation strategies of natural disasters, we can work towards building more resilient and sustainable communities that are better equipped to withstand and recover from these events. Through continued research, innovation, and collaboration, we can strive to minimize the devastating impacts of natural disasters and ensure the safety and well-being of people around the world.。

土地荒漠化英语作文带译文Desertification, a phenomenon where fertile land transforms into arid desert, is an issue of growing concern worldwide.It is a complex process driven by a combination of factors, including climate change, deforestation, and unsustainable agricultural practices. The following essay delves into the causes, consequences, and potential solutions for thispressing environmental challenge.Desertification is often the result of both natural processes and human activities. Droughts, for instance, can exacerbate the process by reducing the availability of water for vegetation. However, it is the human-induced factors thathave accelerated the rate of desertification. Overgrazing, deforestation, and the overexploitation of land foragriculture without proper soil conservation measures are leading contributors to this problem.The consequences of desertification are far-reaching and severe. It leads to a loss of biodiversity as plant andanimal species struggle to survive in the increasingly harsh conditions. Economically, it results in the decline of agricultural productivity, which can lead to food shortages and increased poverty among farming communities. Additionally, desertification can contribute to social instability and mass migration, as people are forced to leave their homes insearch of more hospitable environments.Addressing desertification requires a multifaceted approach. Sustainable land management practices, such as crop rotation, reforestation, and the use of drought-resistant plant species, can help to combat the issue. International cooperation isalso crucial, as many of the world's deserts cross national borders. Efforts to reduce global carbon emissions areequally important, as climate change is a significant factorin the expansion of deserts.In conclusion, desertification is a critical environmental issue that threatens the well-being of both ecosystems and human societies. By understanding its causes and working towards sustainable solutions, we can hope to mitigate its effects and preserve our planet for future generations.土地荒漠化是一个全球日益关注的问题，指的是肥沃土地变成干旱沙漠的现象。

话题08 动物保护Scientists say baby sharks are at risk of being born smaller and without the energy they need to survive because of warming oceans from climate change. Scientists studied epaulette sharks, which live off Australia and New Guinea. They found warmer conditions sped up the sharks' growing process, which meant the sharks were born earlier.John Mandelman, chief scientist of the Anderson Cabot Center for Ocean Life said the findings could be used in the study of other sharks.Mandelman said it is widely believed that epaulette sharks are "hardy," or able to survive difficult conditions. "What it means is that this species is more vulnerable than we thought, and this could be true of other sharks," he added.The scientists studied 27 sharks using the New England Aquarium's reproduction program. Some were raised in average summer water temperatures. Others were raised in higher temperatures. They found the sharks raised in warmer temperatures weighed much less than those raised in average temperatures.One study this year found that worldwide numbers of oceanic sharks and rays dropped more than 70 percent between 1970 and 2018. Overfishing is a main concern, while climate change and pollution also threaten sharks.Carolyn Wheeler, a doctoral student at the University of Massachusetts Boston and the author of the epaulette shark study, said while all the sharks survived, those raised in warmer temperatures were not strong enough to survive for long in the wild. She added that if the sharks are born smaller than usual "they are probably going to have to start looking for food sooner — and they're going to have less time to adjust to their surroundings."Mariah Pfleger, an ocean scientist said the study should serve as a warning to ocean governing agencies that careful supervision is needed to prevent the loss of more sharks." This study further shows that sharks will not be immune to a warming ocean," Pfleger added.1．What does the author want to tell us in paragraph1?A．Oceans get warmer because of climate change.B．Climate change affects sharks’ growing process.C．New finding on short life span of sharks is released.D．Sharks are at risk of dying out.2．What do we know about epaulette sharks?A．They are sensitive to climate change.B．They can survive any difficult situation.C．Climate change has little effect on them.D．The situation is serious even for them.3．What can be inferred according to Mariah Pfleger?A．Overfishing and ocean pollution should be stopped.B．Sharks have to adjust themselves to warmer surroundings.C．Measures should be taken to prevent climate change.D．The number of sharks will continue dropping.4．What can be a suitable title for the text?A．Baby Sharks Struggle to Survive in Warming OceanB．Whether Sharks Can Survive or Not Is a QuestionC．Climate Change Threatens Marine OrganismsD．The Premature Sharks Are Faced With ChallengesWhy did the little boy throw butter out of the window? He wanted to see the butterfly! That’s an old joke you’ve probably heard many times. B utterflies always carry away children.Most insects do not migrate(迁徙), because their life is not long enough. Except for one particular butterfly species-the monarch butterfly. Each November, monarch butterflies land on an unbelievable cross-country migration from the United States and Canada until they reach Mexico, where they overwinter until it’s time to begin their migration back home in March. The butterflies spend their time in concentrated areas of forest where they stick to the branches of trees, forming beautiful vast crowds. Monarchs are a truly important species-and they’re in danger.Just like living things, plants, insects or animals on the planet, monarchs play a vital role in the survival of our ecosystems. Butterflies-just like bees, also in great danger-help pollinate(授粉) plants, making them a significant contributor to crop growth and food production. They also serve as a food sourceto birds and other animals. The population of monarch butterflies has dropped a lot over the past few decades—a destructive 96. 5 percent. This has placed monarchs in danger of moving toward dying out. Several causes have contributed to the monarch’s decline. Climate change, loss of reproductive homes, and deforestation in Mexico’s forests where monarchs overwinter have all affected the butterfly’s migration pattern and home. But the most significant danger is the decline in milkweed, the plant where monarchs lay their eggs, and that serves as the only food source for caterpillars(幼虫). Much of the milkweed decline is due to agricultural practices that either remove this vital plant or destroy it through pesticides(农药). 5．Why do monarch butterflies move to Mexico?A．To survive the cold weather. B．To escape from being hunted.C．To take advantage of the flowers there. D．To cooperate with the bees there.6．How do monarch butterflies affect ecosystems?A．They help birds to catch their food. B．They produce seeds for wild plants.C．They contribute to crop production. D．They bring food to other animals.7．What’s the best title for the passage?A．Monarch Butterflies Migrate B．Butterflies Attract ChildrenC．Fight to Save Monarch Butterflies D．Monarch Butterflies Are in Danger8．What may be talked about following this passage?A．Why monarch butterflies decline.B．How monarch butterflies can be saved.C．How monarch butterflies reproduce.D．Why monarch butterflies migrate.Malaysia’s last rhinoceros(犀牛), Iman, died last November. Some skin, eggs and tissue are all that remain of her. Now, scientists plan to use experi mental technology to try to bring back Malaysia’s rhinos by using cells from Iman and two other dead rhinos.Muhammad, biologist at the International Islamic University of Malaysia, said, “If everything...well and everybody supports us, it’s not impossible.”Malaysia’s rhinos, the smallest among the world’s rhinos, once lived across Asia. But hunting and forest losses reduced their numbers. There are about 80 such rhinos left in Indonesia. But, in Malaysia, thespecies disappeared from the wild in 2015. Iman was 25 when she died at her home in a protected natural area on Borneo island. Tam, the country’s last male rhino, died there in May of 2019. Efforts to get the two to mate and produce young had failed.John Payne of the Borneo Rhino Alliance has worked to save Malaysia’s rhinos for about 40 years. He said that Tam was likely too old to produce good sperm. “To increase the chances of success, one should get sperm and eggs from the rhinos in Indonesia,” he said. But, Payne said Indonesia is not supportive of the idea.The Malaysian scientists plan to use cells from the dead rhinos to create an embryo. The embryo will then be placed into a living rhino, or a closely related animal, such as the horse. The plan is similar to one for the African northern white rhinoceros, of which there are only just two left. Even if it worked, the animals’ lack of diversity could create a threat to their long-term survival, Galli told Reuters.Indonesian scientist Arief Boediono is among those helping in Malaysia. Arief hopes that suecess there will help his country’s rhinos.“It may take five, 10, 20 years. I don’t know,” Arief said. “But there has already been some success involving lab rats in Japan, so that means there is a chance.”For now, however, Iman’s skin will be us ed to create a reproduction of the animal. It will be placed alongside a reproduction of Tam in a Borneo museum.9．What do Muhammad’s words actually mean?A．There are no chances of the successful rescue of Malaysia’s rhinos.B．Indonesia government is to bl ame for rhinos’ rescue and extinction.C．The world organizations should support the rhinos’ rescue.D．There exists hope for the rebirth of Malaysia’s rhinos.10．What accounts for rhinos’ extinction in Malaysia?A．Unexpected disaster. B．Shooting and narrowed habitats.C．Broken food chain. D．Climate changing continuously.11．What’s the best tile for the text?A．Scientists try to bring back Malaysia’s rhinos.B．An experimental technology is facing challenges.C．Welcome to team up to save wild animals.D．Rhinos in danger are drawing attention.12．What is the general tone of the text?A．Indifferent B．Objective. C．Ridiculous. D．Pessimistic.Passage4Voters in Colorado narrowly approved an initiative (计划), setting the stage for the return of gray wolves, which were wiped out in this area by the 1940s. This is the first time that a state has reintroduced an animal like this.The Colorado Parks and Wildlife department will lead the effort to establish a sustainable population of gray wolves in the western part of the state, beginning in 2022 or 2023. The Southern Rocky Mountains, where there used to be a lot of them, contain millions of acres of suitable habitat that could support several hundred wolves or more, biologists say.However, some say it’s unwise to leave the question to voters. “State biologists have previously declined to introduce wolves. There's a reason it's never been done before.” says Shawn Martini, spokesperson for Coloradans for Protecting Wildlife, noting that most supporters are from urban areas and they don't have to live alongside the animal, unlike people living in the countryside. Farmers and hunters don't favor the initiative, either. Farmers worry wolves will kill their cattle while hunters worry they will lose elk (驼鹿) to the predators.On the other hand, according to Jonathan Proctor, a conservationist with the Defenders of Wildlife, reintroducing wolves will restore Colorado's natural balance. They help thin out sick animals, maintaining healthy populations of deer and elk. The remains of wolf kills also provide food for “eaters of the dead”, including wolverines, eagles, and bears. He also emphasizes the experience of living with wolves in other places, like the Northern Rockies, has shown that wolves are not the threat people sometimes make them out to be. Reintroduction program biologists promise to make it a priority to work with people living alongside wolves, providing training and resources to keep the wolves out of the farms in the first place. And a program will be funded to pay farmers for their lost cattle.13．What can we learn about the Southern Rocky Mountains from the text?A．They are heavily populated. B．They were inhabited by wolves.C．They are in the east of Colorado. D．They are home to small animals.14．What's Shawn Martini's opinion about the return of the gray wolves?A．It's unfair to make it happen by voting.B．It's welcomed by urban and rural people.C．State biologists shouldn't have opposed it.D．The wolves should be put somewhere else.15．What will the program biologists probably do first?A．Buy more cattle. B．Reach out to the locals.C．Relocate the wolves. D．Clear the site for wolves.16．What can be a suitable title for the text?A．Wolves are Coming Home. B．No Worries about Wolves.C．Always V ote for What is Right. D．Wolves Help Local Ecosystem.For animals that spend most of their lives in the high trees, gaps in the forest might as well be the Grand Canyon. These gaps are especially hard on gibbons(长臂猴); although larger males can leap across some gaps, females and the young can be cut off from food, companions, and even potential mates. Now, a new study suggests a couple of strong ropes could really help bridge the gap.Gibbons are at risk of extinction across Southeast Asia, largely because of habitat loss. With about 30 individuals left, the Hainan gibbon is considered the rarest primate(灵长类) on Earth. All of these animals live on the Hainan Bawangling National Nature Reserve. In July2014, a typhoon caused landslides across the reserve, creating gaps in the forest that were difficult for these primates to cross.To help reconnect the habitats, professional tree climbers set up an artificial " bridge"made of two mountaineering-grade ropes across a 15-meter-wide valley. Nearly 6 months later,the gibbons started to use the bridge to cross the gap, researchers report today in Scientific Reports. The team documented 52 crossings of a group of eight gibbons, with most walking along one rope while holding on to the second rope for support,which the scientists named"handrail". The gibbons also shimmied underneath the ropes using all arms and legs to the opposite side.Conservationists previously built artificial bridges to help other species such as the Bornean orangutan and the Javan slow loris. But this is the first example of the rare Hainan gibbon using them. The rope bridges could be a short-term solution to reconnect disjointed(脱节的)habitats, the researchers argue. 17．What do we know about gibbons from the second paragraph?A．Rarely are gibbons seen for the population decline.B．Habitat loss was to blame for gibbons' dying out.C．Gibbons couldn't cross gaps caused by a typhoon.D．The natural disaster may have posed a threat to gibbons.18．What does the underlined "shimmied" likely mean?A．Lifted. B．Grabbed. C．Swung. D．Spread.19．What is the text mainly about?A．The reasons for gibbons' dying out. B．The importance of saving gibbons.C．The measures to save gibbons. D．The solution to gibbons' habitat loss.1．B2．D3．C4．A【分析】这是一篇说明文。

《作物育种学总论》习题Exercises in general introduction of crop breedingChapter 1 breeding objectives1.terms: breeding objectives, biological yield, economic yield, harvest index, plant breeding, breeding for high photosynthetic efficiency2.what are the basic requirements of modern agriculture for crop varieties?3.what are the principles for formulating breeding objectives?4.what are the main objectives of crop breeding?5., how can we correctly formulate a practical breeding target?6., why can crop yield increase through dwarf breeding?7., formulate a breeding target for a particular crop for a region you are familiar with and explain why.The seco nd chapter is the breed ing mode and varieties of cropsFloral structure and flowering habits of the wheat, corn, cotton, soybeans and other crops・ What are the floral structure and flowering habits conducive to cross pollination? What are thefloral structure and flowering habits conducive to self pollination?Combining the specific crops, the genetic effects of selfing and outcrossing were briefly described・What are the types of crops and what are the basic characteristics of them?What are the breeding characteristics of different types of populations?The third chapter, Germplasm Resources1.concepts: germplasm resources, origin centers, primary centers, secondary centers, native crops, secondary crops, genetic diversity centers, gene banks, primary gene pools, secondary gene pools, and three gene pools2.briefly describe the role of germplasm in crop breeding・3.briefly describe the characteristics and utilization value of local germplasm resources・4.briefly describe the characteristics and utilization value of foreign germplasm resources・What is the role of the theory of 5. Vavilov origin center in crop breeding?6.how to differentiate between primary and secondary centers?7.the main contents and identification methods of crop germplasm resources are discussed・8., what is the significance of establishing the crop gene pool? How to build a crop gene bank?9., what is the significance of establishing a database of crop germplasm resources? How to establish a database of crop germplasm resources?10.what is the necessity and significance of excavation, collection and preservation of germplasm resources?The fourth chapter is introduction and Domestication1.what are the concepts and basic principles of introduction and domestication?2.what are the factors affecting introduction and the law of introduction?The fifth chapter chooses breeding1.describe the basic principles and procedures of breeding・The sixth chapter is cross breeding1.types of cross breeding can be divided into two types according to their guiding ideology What are the respective genetic mechanisms?2.why is it the key to cross breeding to choose the parents correctly? What's the point?3., how to understand the four principles of parental selection in cross breeding?4., what are the advantages and disadvantages of using genetically diverse materials as parents? How do you understand the distance between parents and their parents?5.why should parents be highly cooperative?6.why is hybridization one of the most important factors that affect the success of cross breeding? What are the hybrid ways? How about the genetic proportion of each parent in single cross, three handed, four handed and double crosses? Why do you put the good agronomic parents on the last cross in the three and four crosses?7.explain genealogy, mixed method, derivative system method and single granule transmission method, and give a brief account of their respective work points. Compare their advantages and disadvantages and their applications・The seventh chapter is backcross breeding1.what is backcross breeding? What are the uses and limitations of backcross breeding? What is the most effective breeding in backcross breeding?2.what is a recurrent parent and a non recurrent parent? What roles do they play in backcross breeding? What problems should we pay attention to when choosing recurrent parents and non recurrent parents?What is the genetic effect of 3. backcross? What's the difference between selfing and genetic effects?4., the characters of dominant and recessive single gene control, as well as the backcross breeding process of quantitative characters were briefly described・The eighth chapter is the utilization of HeterosisThe 1. nouns explain heterosis, specific combining ability, test cross, test cross species, test species, one ring system, second ring system, gametophyte self incompatibility, sporophyte self incompatibility and cytoplasmic hybrid2.what are the approaches to utilize crop heterosis? What are the characteristics of each?3.what are the methods of measuring heterosis in crops? How to measure?FourPrinciples and reasons for selection of parents of hybrid varieties ・5.what are the basic conditions for utilizing crop heterosis? What types of crop hybrids are there in6.?What are the characteristics of crop heterosis in 7. crops?8.what are the main directions for the study of Heterosis in maize, rice, cotton, wheat and so on? Why?9.,what are the genetic causes of Heterosis in crops? What do you think of these interpretations?10.what methods are used to determine the combining ability? What are the characteristics of these methods?11.what is cytoplasmic cytoplasmic male sterility? How does this sterility utilize heterosis?12.what is the difference between sporophyte sterility and gametophyte? What are the characteristics of each?13.,there are several types of pollen abortion in male sterility What are the characteristics of each?14.what are the abnormal physiological and biochemical aspects of male sterility in plants?15., what are the conditions for the application of sterile lines?16.what methods can be used for the breeding of restorer lines?17.what principles should be followed in the selection of hybrid varieties? Why?18.how to identify the genetic type of genic male sterile material?How was the germplasm of 19. photoperiod and photoperiod induced male sterility obtained?The ninth chapter is mutation breeding1.what are the species, radiation sources, and major characteristics of the major physical mutagens?2.the materials of radiation mutation treatment and corresponding treatment methods are discussed・3.what are the irradiation intensity and dose intensity? What is its unit? How do you convert new and old units?4.how do you determine the optimum dose of radiation?5.what are the types, properties and principles of the main chemical mutagens? What problems should we pay attention to in using?6.how to determine the concentration and treatment time of chemical mutagens?7., what is the difference between mutation breeding and other breeding (such as cross breeding) in the treatment of future generations?8.why does mutation breeding require close planting in Ml?9.to illustrate the achievements of mutation breeding in Crop Genetics and breeding and agricultural production・10.what are the characteristics and trends of plant mutation breeding?The tenth chapter is distant hybridization breeding1.what is distant hybridization? What is the role and significance of distant hybridization in crop genetics, breeding and scientific research?2.the characteristics and difficulties of distant hybridization were discussed.3., try to explain the reasons for the incompatibility of distant hybridization and the ways to overcome it.4.hybrid sterility and why die? How to overcome?What is the difference between the isolation of 5. Distant Hybrids and that of interspecific hybridization?6.how to overcome the instability of distant hybridization progeny?What is the principle of induction of haploid in 7. distant crosses?8.what are alien addition lines and alien substitution lines?Can il be used directly in agricultural production? How to make use of it in Crop Genetics and breeding?9.to discuss the advantages and disadvantages of somatic hybridization.The eleventh chapter is ploidy breeding1.what are the main ways to induce polyploidy?2.what are the main ways of artificially inducing haploid?3.,the significance of ploidy breeding in plants was discussed・4.how does plant ploidy breeding combine with other breeding methods?5., six times triticale lacks D genome, poor quality of grain. How do you think it improved?The twelfth chapter is disease resistant breeding1., the main role of pest resistance breeding in modernagricultural production?2.. What are the physiological races, physiological, biological and differential hosts?3.what is the gene pair theory of genes?4.what is vertical resistance and horizontal resistance?5., the main links of breeding for disease resistant insects?6.how to maintain the stability of resistance to disease resistant varieties?The thirteenth chapter stress resistant breeding1.main species of crop adversity?2.. The meaning of drought resistanee and salt tolerance of crops?3.general procedures for crop stress resistance breeding?4.main methods of crop stress resistance identification?The fourteenth chapter, group improvement and recurrent choice1.,the concept and function of group improvement・2.principles of population improvement・3., the basic process and main link of population improvement・4., the similarities and differences between composite varietiesand synthetic varieties・5.how do we synthesize base populations for population improvement?6.,how does the recurrent selection approach the combination of population impTovement and breeding practice?SevenWhat are the recurrent selection methods within a population? What are the characteristics of each?8.,what are the similarities and differences between groups and groups?9., in what circumstances is it suitable to apply compound cycle selection?10.why into Recessive Genic Male sterile gene is based on recurrent selection of self pollination and cross pollinated crops?The fifteenth chapter is the experimental technique of crop breeding1.explain the concepts: marginal effects, growth competition, regional trials, varietal adaptability, and varietal stability2.what are the basic requirements for field trials? How can the test error be minimized?3.what are the factors that affect the design of a residential district? How do you deal with these factors?4.,how to overcome inter cell compelition?5.how do you conduct a line comparative test?6.what are the conditions for applying for a regional trial? What standards are you up to?7.how about regional test and production test?8.what are the methods and procedures for the stability parameterestimation using the average number of varieties as the parameter and the adaptive estimation method based on the environmental index?The sixteenth chapter, seed production and management1.what conditions should be applied for the varieties that have been applied for approval?2., what are the similarities and differences between China, Japan, the United States and European countries in their species management systems?What are the substantial and major causes of the 3. species，hybrid degradation? How to prevent?4.in China, self pollination and cross pollination often crop seed production method, the main differenee breeding method and cycle selection proposed in recent years strains breeding method and self propagation method mixed in technology is what?5.show three methods of producing two representative types of parent stock, and point out their substantive differences and their theoretical basis.6.what are the two methods for the production of inbred stock? What，s the difference between them?7.how to speed up breeding?How to select isolation zone in 8. parent breeding and hybrid seed production? How do you determine your parents， ratio?9.what is the key point in regulating the sowing date and ensuring the flowering time in hybrid seed production?Plant breeding, biotechnology, exercisesChapter 1 cell engineering and crop breeding1.what are the main ingredients of the culture medium?2.what is the genetic basis for somaclonal variation in somatic cells?3.how to breed new varieties by somatic cell cloning and variation?4.. What is the practical value of haploid cell culture in crop breeding?What is the difference between microspore development and normdl microspore development under 5. culture conditions?6.what are the factors that affect anther culture?7., how can cell engineering be used to overcome theincompatibility of distant hybridization?The second chapter, transgenic technology and crop breeding1.what is GM crop breeding? What are the contents of its research?2.. Advantages and disadvantages of transgenic breeding and their relationship with conventional breeding・3.procedures for breeding transgenic crops・4.what are the commonly used transgenic methods?5.what are the common methods for identification of transgenic plants?6.the mode and characteristics of exogenous gene integration.Causes and solutions of 7. gene silencing・8.isolation of foreign genes in transgenic plants・9.specific ways of breeding transgenic crops・10.biosafety principles of genetically modified crops.The third chapter is molecular marker assisted selection breeding1.types and genetic characteristics of several major molecular markers・2.订lustrate the principles and methods of gene mapping for important agronomic traits.3.how to understand the development of molecular marker technology and inject new vigor into crop breeding work?PAGEPAGE 5***[JimiSoft:, Unregistered, Software, Convert, Part, Of, File, Read, Help, To, Know, ONLY, How, To, Register.]***。

英语作文饥饿与解决问题演讲稿全文共3篇示例，供读者参考篇1Hunger: A Crisis That Demands Our Urgent ActionHello everyone, my name is Sara and I'm a high school student here to talk about one of the gravest challenges facing our world today - hunger. While many of us are fortunate enough to have access to abundant food, billions of people around the globe are trapped in the vicious cycle of poverty and malnutrition.The statistics are staggering: according to the World Food Programme, 828 million people go to bed hungry every night. That's roughly 1 in 10 people on our planet. And the consequences of hunger are far-reaching, impacting not just physical health but also mental development, education, and economic productivity.I still vividly remember learning about the devastating effects of famine in history class - how entire populations were decimated, how children were left stunted and vulnerable to disease, and how the fabric of societies unraveled. And yet, evenin the 21st century, hunger remains an all too present reality for far too many.The Roots of HungerBut what causes hunger in the first place? The reality is that hunger is a complex and multifaceted issue, with various contributing factors. From climate change and environmental degradation to conflict and displacement, the roots of hunger run deep.In many parts of the world, erratic weather patterns, droughts, and floods are wreaking havoc on agricultural systems, destroying crops and jeopardizing food security. Compounding this are unsustainable farming practices that deplete soil fertility and disrupt delicate ecosystems.Political instability and armed conflicts have also forced millions to flee their homes, leaving them without access to food, clean water, and basic resources. The ongoing war in Ukraine, for instance, has disrupted vital grain exports and pushed millions more into food insecurity.And let's not forget the role of poverty and economic inequality. When families are trapped in cycles of poverty, unableto afford nutritious food or invest in sustainable agriculture, hunger becomes an inescapable reality.The Impact of HungerBut the consequences of hunger go far beyond mere hunger pangs. Lack of proper nutrition, especially in the critical first few years of life, can impair cognitive development, stunt physical growth, and increase susceptibility to diseases.Children who suffer from malnutrition are more likely to struggle in school, perpetuating cycles of poverty and limiting their future prospects. The effects of hunger can also ripple across generations, as malnourished mothers are more likely to give birth to underweight babies, setting off a vicious cycle that's difficult to break.On a broader scale, hunger poses a significant barrier to economic development and social progress. When large swaths of a population are struggling to meet their basic nutritional needs, productivity suffers, healthcare costs soar, and entire nations are held back from reaching their full potential.Hunger is not just a humanitarian crisis; it's an economic and societal crisis that demands our collective attention and action.Solutions Within Our ReachBut amid this seemingly bleak landscape, there is hope. Solutions to hunger do exist, and we have the knowledge, resources, and technology to make a tangible difference.One of the most powerful tools in our arsenal is sustainable agriculture. By embracing environmentally-friendly farming practices, such as crop rotation, water conservation techniques, and agroforestry, we can boost yields while preserving our planet's precious resources.Investing in rural infrastructure, such as better roads, storage facilities, and irrigation systems, can also go a long way in enhancing food security and reducing post-harvest losses.We must also prioritize gender equality and women's empowerment. When women have equal access to resources, education, and decision-making power, they can become catalysts for change, driving agricultural productivity and ensuring their families are well-nourished.Additionally, we need to rethink our food systems and supply chains, minimizing waste and ensuring that nutritious food reaches those who need it most. Innovative solutions like urban farming, vertical agriculture, and food fortification can play a crucial role in this effort.And let's not forget the power of education and awareness. By promoting nutrition literacy and teaching sustainable farming practices, we can equip communities with the knowledge and skills they need to tackle hunger head-on.A Call to ActionBut none of these solutions will be effective without collective action and a shared commitment to ending hunger. Governments, NGOs, businesses, and individuals alike must join forces and prioritize this issue on the global agenda.We must hold our leaders accountable, demanding policies and investments that address the root causes of hunger and promote long-term food security. We must support organizations and initiatives that are making tangible progress in this fight, whether through emergency relief efforts or sustainable development programs.And as individuals, we can make a difference through our choices and actions. By supporting local farmers and sustainable food systems, reducing food waste, and using our voices to advocate for change, we can be part of the solution.My fellow students, we are the inheritors of this planet, and the fate of billions rests on our shoulders. We cannot afford to be complacent or apathetic in the face of such a pressing crisis.Hunger is not just a statistic or a far-away problem; it's a human tragedy that robs people of their dignity, potential, and basic rights. It's a threat to global stability, economic progress, and the very future we hope to build.So let us make a commitment today, to stand up against hunger, to champion sustainable solutions, and to work tirelessly until every person on this planet has access to adequate, nutritious food.The path ahead will not be easy, but our collective determination and compassion can overcome any obstacle. Together, we can build a world where no child goes to bed hungry, where families can thrive, and where hunger is relegated to the pages of history books.Thank you.篇2Hunger and Finding Solutions: A Call to ActionHello everyone. My name is Maya and I'm a high school student here to talk to you today about one of the biggest issues facing our world - hunger and malnutrition. This is a problem that impacts millions of people globally, including many children and families right here in our own communities.I know it can be easy to feel disconnected from such a vast and overwhelming crisis. But hunger is something that ties us all together as human beings. Each of us needs food and nutrients to survive and thrive. Hunger doesn't discriminate based on race, gender, age or borders. It's a universal issue that demands universal solutions.The numbers are staggering. According to the World Food Programme, 828 million people go to bed hungry every night. That's roughly 1 in 10 people on this planet without enough to eat. In many countries, the statistics are even more dire - in places like Afghanistan and Yemen, over 30% of the population is undernourished.And malnutrition doesn't just mean starvation. It encompasses vitamin and mineral deficiencies that can have devastating impacts, especially on children. Poor nutrition causes stunting, wasting, and needless deaths from common childhoodillnesses. The long-term effects rob societies of opportunity by impairing physical and cognitive development.Some of the worst hunger emergencies in recent years have been driven by conflict and climate shocks like drought and flooding. From Syria to South Sudan to Somalia, warfare has destroyed food systems and precipitated famine conditions. The climate crisis is increasing food insecurity too, damaging crop yields and disrupting livelihoods in vulnerable regions.But even in more stable environments, far too many people struggle to afford or access sufficient healthy food. Poverty, food deserts in urban areas, inefficient supply chains - these factors perpetuate cycles of hunger and malnutrition even in wealthy nations. The COVID-19 pandemic also caused a sharp rise in global food insecurity as incomes dropped and supply lines faltered.As young people, this is an issue that should matter deeply to all of us. Hunger threatens our present and our future. It prevents children from attending school and realizing their full potential. It fuels unrest and desperation that can destabilize entire regions. And left unaddressed, it could threaten our ability to build a sustainable world for generations to come.So what can we do to solve this crisis? The solutions will require commitment and action at every level - from the personal to the political.At an individual level, each of us can make more ethical and sustainable food choices. Cutting back on food waste, supporting local farms and food systems, and maintaining a plant-based diet as much as possible are simple steps that reduce strain on the environment and food supplies.We can also use our voices and our values to advocate for change. Call on schools, businesses, and community organizations to source food ethically and prioritize sustainability. Push governments to increase humanitarian food aid, invest in resilient agriculture and commit to the UN's Sustainable Development Goal of Zero Hunger by 2030.Solving hunger will also require addressing its root causes like poverty, inequality and conflict. That means doubling down on efforts to promote quality education, economic development, women's empowerment and peaceful conflict resolution worldwide. These are the building blocks of stable, productive societies with secure food systems.And critically, we must act now to mitigate the climate crisis that is already compounding global hunger and putting morepeople at risk. Reducing emissions, pursuing clean energy solutions, and adapting food production methods will be key to preventing worst-case scenarios in the coming decades.I know it can feel overwhelming to take on such a vast, intractable problem. But throughout history, grassroots movements of passionate activists have catalyzed seismic changes once thought impossible. From the abolition of slavery to women's suffrage to the fall of apartheid - these epic struggles were all won by people who refused to accept the status quo.So I'm asking all of you to join this worldwide movement to eradicate hunger and malnutrition once and for all. With our energy, voices and collective action, we can turn the tide. We can build a future where everyone, everywhere has reliable access to sufficient healthy and sustainable food.This is the great moral issue of our lifetimes, and history has shown that willful determination from younger generations is the catalyst for transformative change.So let's get to work - volunteering, raising funds and awareness, lobbying leaders and policymakers. Let's put hunger on the top of the agenda and keep it there until this scourge has been eliminated.Think of the billions of people, past, present and future, whose lives depend on us solving this crisis. They're hungry, not just for food, but for justice, dignity and equity on this planet we all share.Thank you, and let's go forward from here as a unified force for human prosperity and welfare. Our actions today will help write a better story for generations to come.篇3Hunger: A Worldwide Crisis Demanding Innovative SolutionsHello everyone. My name is Maya and I'm a high school senior here to talk to you today about an issue that impacts millions of people around the world - hunger. It's a problem that may seem distant if you're fortunate enough to have regular access to food. But hunger is very real and has devastating consequences for those experiencing it.I'd like to start by sharing some statistics that highlight the scale of the crisis. According to the World Food Programme, 828 million people go to bed hungry every night. That's roughly 1 in 10 people globally who don't have enough food. In 2021 alone, 193 million people across 53 countries experienced acute hunger requiring urgent assistance. These numbers are staggering.But what do they really mean? Hunger isn't just an uncomfortable rumbling in your stomach. Prolonged hunger weakens the body and mind. It makes people more susceptible to disease and undermines human potential. For children suffering from malnutrition, the effects can be permanent - stunting physical and cognitive development. According to UNICEF, a staggering 45% of deaths among children under 5 are linked to undernutrition. That's 3.1 million young lives cut short each year due to lack of food.So how did we get here? There are a number of interconnected factors driving global hunger:Poverty - Simply not having enough money to purchase food is a root cause for many. The World Bank estimates 9.2% of the world's population lives in extreme poverty on less than 2.15 a day.Climate Change - Rising temperatures, more frequent natural disasters, and environmental degradation are disrupting food production and supply chains worldwide.Conflict - War breeds instability and displaces populations, cutting off access to food sources. According to the World Food Programme, 60% of the world's hungry live in areas affected by conflict.Economic Shocks - From the Covid-19 pandemic to the war in Ukraine, global crises over the last few years have caused spikes in food insecurity as supply chains broke down.The reality is that hunger impacts all of us eventually, whether through inflated food prices, instability from conflict, or other societal strains traced back to lack of nutrition. So this isn't just a problem for the poor - it's a problem for everyone that demands solutions.Solving hunger is undoubtedly a huge challenge spanning issues from agriculture to poverty to climate change. But I remain hopeful that human innovation and determination can help us make progress. Here are a few key areas where solutions may be found:Food Production - We need to invest in sustainable agriculture to boost crop yields through drought/disease resistant seeds, precision farming techniques, and other innovations. Reducing food waste throughout supply chains is also critical, as up to 40% of food currently goes uneaten.Economic Development - Policies promoting economic growth, job creation, and social safety nets can help lift people out of poverty and improve food access. Education, especially for girls and women, is a powerful tool as well.Climate Resilience - From developing drought-tolerant crops to building infrastructure to withstand disasters, preparing for the impacts of climate change on food systems is essential. Transitioning to clean energy can also reduce emissions driving climate change.Conflict Resolution - Ending civil wars and violence through diplomacy and peacekeeping efforts can stabilize communities and restore access to food sources. Protecting vulnerable displaced populations is key.Innovative Solutions - New technologies like vertical farming, lab-grown meat, delivery drones and other innovations have the potential to transform food production and distribution systems.Of course, there is no silver bullet. Combating hunger requires a comprehensive approach across many sectors and societies, driven by strong leadership and collaboration between governments, NGOs, corporations and everyday people like you and me.But we can't forget that behind every chart and statistic about hunger, there are real human lives being impacted - families worried about where their next meal will come from, children missing out on their full potential. Hunger robs peopleof their dignity and deprives them of the chance to live their lives to the fullest.That's why solving hunger must be a top priority - not just because it's smart for the global economy and societal stability, but because it's quite simply the right thing to do. As global citizens, we have a moral imperative to ensure that every person has access to adequate food and nutrition.So in closing, I urge all of you to join me in making a commitment today. Whether it's advocating for hunger relief efforts, changing your personal consumption habits, or even pursuing a career that can contribute solutions, we all have a role to play. Only by coming together and channeling our ingenuity into action can we hope to achieve a zero hunger world in our lifetimes.Thank you.。

SECTION A The role of governments in environmental management is difficult but inescapable, 政府在环境管理方面所扮演的角色及困难又不可避免Sometimes. the state tries to manage the resources it owns. and does so badly有时候，国家尝试着自己来管理资源并且做的很差劲.Often,however,governments act in an even more harmful way然而，政府却常常采取一种更加有害的方式. They actually subsidise the exploitation and consumption of natural resources.他们补贴开采和消耗自然能源的行为 A whole range of policies一系列的所有政策,from farm price support to protection for coal-mining,从农产品价钱的保障到对煤矿的保护do environmental damage and (often) make no economic sense造成了环境破坏而且没有经济效益. Scrapping them offers a two-fold bonus:废除它们能带来双重好处 a cleaner environment and a more efficient economy.更加干净的自然坏境和更加高效的经济 Growth and environmentalism can actualty go hand in hand.种植和环境主义能手牵手齐步发展if politicians have the courage to confront the vested interest that subsidies create.如果政治家们有勇气来面对补贴所带来的合法收益SECTION B No activity affects more of the earth's surface than farming. 没有哪项人类活动比农业对地球表面造成更大的影响It shapes a third of the area, not counting Antarctica. and the proportion is rising. 它塑造了三分之一地区的地面状况，这些地区并不包含南极，而且比例正在增大World food output per head has risen by 4 per cent between the 1970s and 1980s mainly as a result of increase in yields from land already in cultivation, but also because more land has been brought under the plough.作为已开垦土地的产量上升的结果，世界人均粮食产量在1970s到1980s上升百分之四，但是也有更多土地被开垦的原因 Higher yields havebeen achieved by increased irrigation, better crop breeding, and a doubling in the use of pesticides and chemical fertillisers in the 1970s and 1980s. 通过被增加的灌溉、更好的作物品种、杀虫剂和化学肥料的加倍使用，粮食产量的提高在1970s 到1980s得到实现SECTION C All these activities may have damaging environmental impacts.所有的这些活动都有破坏环境的方面， For example例如. land clearing for agriculture is the largest single cause of deforestation;清理土地来作为农用是森林砍伐的一个最大的原因 chemical dertilisers and pesticides may contaminate water supplies化肥和杀虫剂会污染水资源; more intensive farming and the ababdnment of follow periods tend to exacerbate soil erosion更加集约的农业和后期土地的荒弃将会恶化土壤浸蚀; and the spread of monoculture and use of high-yielding varieties of crops have been occompanied by the diappearonce of old varieties of food plants which might hove provided some insurance against pests or diseases in future. 而且在单一作物种植的普及以及高产类作物种植的同时，伴随着老的各种各样植株的消失，而这些消失的植株可能能为将来的虫害和疾病提供预防Soil erosion threatens the productivity of land in both rich and poor countries. 不论是在富有还是贫穷的国家土壤侵蚀都威胁着土地的生产力The United States, 在美国where the most careful measurements have been done进行了一项最为仔细的测量已经被进行了, discovered in 1982 that about one-fifth of its farmland was loosing topsoil at a rate likely to diminish the soil's productivity. 发现在1982年五分之一的农业用地的表层土正在以一个会削弱土地生产力的速度流失The country subsequently embarked upon a program to convert 11 per cent of its cropped land to meadow or forest.美国于是投资开展了一个将百分之十一的农业用土转变为牧场或者是森林Topsoilin India andChina is vanishing much faster than in America. 印度和中国的表层土正在以比美国更快的速度流失SECTION D Government policies have frequently compounded the environmental damage that farming can cause.政府政策常常会混合了农业能造成的环境破坏ln the rich countries在经济大国. subsidies for growing crops and price supports for farm output drive up the price of land.对种植谷物的补贴和对农业生产的支持使得地价飞涨The annual value of these subsidies is immernse每年用作补贴的金额都是巨大的:about $250 billion大概 2.5亿美元,or more than all World Bank lending in the 1980s或者超过世界上所有银行在1980S的借出.To increase the output of crops per acre为了增加每英亩土地上的粮食产量, a farmer's easiest option is to use more of the most readily available inputs一个农民最简单的选择就是更多的使用有效的投入:fertilisers and pesticides化肥和农药. Fertiliser use doubled in Denmark in the period 1960-1985 丹麦在1960-1985期间化肥使用量翻倍and increosed in The Netherlands by 150 per cent并且荷兰的用量翻了1.5倍.The quantity of pesticides applled has risen too:杀虫剂的使用总量也已经上升了 for example,by 69 per cent in 1975-1984 in Denmark,例如，丹麦在1975年到1984年上升了百分之69，with a rise of 115 per cent in the frequency of application in the three years from 1981.从1981年后的3年里频繁的使用带来了达到115%的上升in the late 1980s and eorly 1990s some efforts were made to reduce farm subsidles.在20世纪80年代后期和90年代初期在减少农业补贴方面做了一些努力The most dramatic example was that of New Zealand最戏剧化的例子是新西兰,which scrapped most farm support in 1984.它在1984年废除了大部分的农业补贴A。

土地沙漠化的原因及治理措施英语作文全文共10篇示例，供读者参考篇1Oh my goodness! Do you know that our land is turning into a desert? It's called land desertification. It's a big problem, but don't worry, I'll tell you all about it and how we can fix it!There are many reasons why land becomes desert. One big reason is over-farming. When farmers keep planting crops in the same land without giving it a break, the soil loses all its nutrients and becomes dry and useless. Another reason is deforestation. When trees are cut down, the land becomes dry and sandy, like a desert. Pollution is also a big problem. When factories release harmful chemicals into the air, it can make the land unhealthy for plants to grow.But don't worry! There are ways to fix land desertification. One way is to plant more trees. Trees help to keep the soil moist and healthy. Another way is to rotate crops. This means planting different crops in the same land each season. It helps to keep the soil full of nutrients. We can also stop using harmful chemicalsand pollution. Instead, we can use natural fertilizers and keep the air clean.So remember, we all need to work together to stop land desertification. Let's plant more trees, rotate our crops, and keep our land clean and healthy. Together, we can make a difference!篇2Land desertification is a big problem that we are facing these days. Do you know why the land is becoming desert? There are several reasons for this.Firstly, overgrazing is a major cause of land desertification. When too many animals eat all the plants in an area, there is nothing left to hold the soil together. Then, when the wind blows, it carries away the soil, leaving behind barren land.Secondly, deforestation also contributes to land desertification. When trees are cut down, the soil becomes exposed to the hot sun and strong winds. Without the protection of the trees, the soil becomes dry and barren, turning into desert.Lastly, climate change is another factor that leads to land desertification. Global warming causes the temperature to rise, making the land dry up and turning it into desert.But don't worry, there are ways to prevent and control land desertification. Planting trees is a great way to prevent desertification. Trees help to hold the soil in place and provide shade for the land. We can also practice sustainable farming methods, such as crop rotation and terracing, to prevent erosion and keep the soil healthy.In conclusion, we need to take action to stop land desertification. By protecting our land and practicing sustainable farming methods, we can ensure that our planet remains green and healthy for future generations. Let's work together to save our land from turning into desert!篇3Why do deserts form and how can we fix them? Let's explore the causes of land desertification and some solutions!Land desertification happens when dry areas turn into deserts because of things like overgrazing, deforestation, and climate change. Overgrazing means there are too many animals eating the plants, which can make the soil dry and unable to grow new plants. Deforestation is when people cut down trees for wood or to make room for farming, which can make the land dry and lose nutrients. Climate change is when the Earth'stemperature gets hotter, causing less rain to fall and making the soil dry up.But don't worry, there are ways to fix desertification! One solution is to plant more trees and grass to help hold the soil in place and provide shade. Another solution is to use less water and find ways to conserve it, like using drip irrigation for farming. We can also try to reduce carbon emissions to slow down climate change and protect our planet.By working together and taking care of our land, we can stop desertification and create a healthy environment for plants, animals, and people. Let's protect our planet and make sure it stays green and lush for generations to come!篇4Oh! Hi everyone! Today I want to talk about the reasons for land desertification and some ways to deal with it. So, let's get started!First of all, do you know why land becomes desert? Well, one of the reasons is overgrazing. That means when there are too many animals eating the grass and plants on the land, it can't grow back fast enough and the soil becomes dry and can't hold on to water. Another reason is deforestation. When people cutdown trees and plants, it can make the land lose its nutrients and become dry and barren. Climate change is also a big factor in desertification. When the weather gets too hot or too dry, it can make the soil lose its moisture and become desert-like.But don't worry, there are ways to help stop land desertification! One way is to plant trees and bushes. Trees and bushes can help hold onto water and nutrients in the soil, and they provide shade which can keep the land cool. Another way is to use less water. When we use less water for things like watering our lawns or washing our cars, we can help keep the land from drying out. Also, we can use sustainable farming practices. This means taking care of the land and rotating crops so that the soil stays healthy and doesn't become desert-like.So, you see, there are things we can do to help stop land desertification! Let's all work together to protect our land and keep it healthy and green. Bye for now!篇5Title: Let's Learn about DesertificationHey guys, do you know what desertification is? It's when the land turns into a desert because of things like climate change,overgrazing, deforestation, and poor farming practices. It's a big problem that we need to learn about and find solutions for.One of the reasons why desertification happens is because of climate change. When the weather gets hotter and drier, it makes it harder for plants to grow and for the soil to stay healthy. This can lead to the land becoming dry and sandy, just like a desert.Another reason is overgrazing by animals. If there are too many animals eating all the plants in an area, the soil can be damaged and lose its nutrients. This makes it easier for the land to turn into a desert.Deforestation is also a big problem when it comes to desertification. When trees are cut down, the soil loses its protection from the sun and the rain. This can make the land dry up and turn into a desert.But don't worry, we can do something to help stop desertification. We can plant more trees to provide shade and protect the soil. We can also use sustainable farming practices that help the land stay healthy, like rotating crops and using less water.Remember, it's important for all of us to learn about desertification and do our part to protect the land. Let's work together to keep our planet green and healthy!篇6Hello everyone! Today I want to talk about why land desertification happens and how we can fix it. So let's get started!First of all, land desertification happens when the land becomes dry and barren. This can be caused by a lot of things like overgrazing, deforestation, and climate change. When we take too many animals to graze on the land, they can eat all the grass and plants, and the soil becomes exposed and starts to dry out. With no plants to hold the soil together, it can easily be blown away by the wind, creating a desert. Deforestation is when we cut down a lot of trees, which can also lead to land desertification because the roots of trees help to hold the soil in place. And climate change makes everything worse because it can cause droughts and make the land even drier.But don't worry, there are things we can do to help fix land desertification! One thing we can do is plant trees and grass to help hold the soil in place. This can help prevent erosion andstop the land from turning into a desert. We can also use techniques like terracing and contour plowing to help conserve water and prevent soil erosion. These techniques help to slow down the flow of water and trap sediment, which can help to restore the land.So remember, we can all do our part to help stop land desertification. Let's plant more trees, protect our forests, and take care of the land so it can stay healthy and green. Together, we can make a difference and keep our planet beautiful for generations to come. Thanks for listening! Bye!篇7Land desertification is a very serious problem that we are facing now. It is caused by various reasons, such as overgrazing, deforestation, and improper farming practices.One of the main reasons for land desertification is overgrazing. When there are too many animals grazing on the land, the grass and other vegetation are eaten up, leaving the soil exposed to wind and water erosion. This leads to the soil becoming barren and unable to support plant growth.Deforestation is another major cause of land desertification. When trees are cut down for timber or to make space foragriculture, the soil loses its ability to retain water. This results in soil erosion and eventually leads to the land becoming desertified.Improper farming practices, such as excessive use of chemical fertilizers and pesticides, can also contribute to land desertification. These chemicals can degrade the soil quality, making it less fertile and prone to erosion.To address the problem of land desertification, there are several measures that can be taken. One important solution is to practice sustainable land management. This means using farming methods that do not harm the environment, such as organic farming and crop rotation.Another effective way to combat land desertification is to plant trees and vegetation to restore the soil's fertility and prevent erosion. This can be done through afforestation and reforestation projects.In addition, it is important to raise awareness about the importance of preserving the land and the consequences of desertification. By educating people about the causes and effects of land desertification, we can all work together to protect our environment and ensure a sustainable future.篇8Yo! Let me tell you about desertification of land, which is like, when land turns into desert. Super not cool, right? But why does this happen and how can we fix it? Let's dive in!So, the main reasons for land desertification are like, overgrazing by animals, deforestation, and overuse of land for farming. When animals eat too much grass, it makes the soil go dry and sandy. And when trees are cut down, there are no roots to hold the soil in place, so it blows away in the wind. And when people farm the land too much, it loses all its nutrients and turns into dust.But don't worry, there are ways to fix this! We can plant trees to stop the soil from blowing away, and we can use sustainable farming practices to keep the soil healthy. We can also build walls to stop the wind from blowing the soil away, and we can rotate crops so the land has time to rest and regain its nutrients.So yeah, desertification is a big problem, but if we all work together, we can totally fix it. Let's keep our land healthy and green for future generations! Peace out!篇9Land desertification is a big problem that we need to pay attention to. Do you know what causes land desertification and how we can fix it? Let me tell you all about it!The main reason for land desertification is overgrazing, deforestation, and improper agricultural practices. When too many animals are grazing in one area, they eat all the plants and grass, leaving the soil exposed to erosion. Without plants to hold the soil in place, it can easily be blown away by the wind or washed away by rain. Deforestation also contributes to land desertification because trees help keep the soil in place and provide shade and moisture for other plants to grow. Improper agricultural practices, such as using too much fertilizer or not rotating crops, can also degrade the soil and lead to desertification.But don't worry, there are ways we can help prevent and fix land desertification! One way is to practice sustainable land management, which means using the land in a way that protects it for future generations. This includes planting trees, rotating crops, and using less water and chemicals. Another way to combat land desertification is to build barriers such as windbreaks and fences to protect the soil from erosion. We canalso restore degraded land by planting native trees and grasses and creating terraces to help trap water and prevent soil erosion.By taking these measures, we can help stop land desertification and protect our environment for future generations. Remember, the land is precious, and it's up to us to take care of it! Let's work together to keep our land healthy and green!篇10Title: Causes of Land Desertification and Measures to Control ItHey guys! Do you know why some lands become deserts? Let's find out together! First of all, do you know what desertification means? It means when the land turns into a desert because of dry weather, overgrazing, deforestation, and other bad things happening to it. So, what are the reasons behind desertification?One of the main reasons is deforestation. When people cut down trees without planting new ones, the land becomes bare and can't hold onto water and nutrients. This makes the soil dry and useless for growing crops. Another reason is overgrazing by animals. When there are too many animals eating all the plants,there won't be anything left to keep the soil in place. The soil will then be blown away by the wind, leaving barren land behind.But don't worry, there are ways to control desertification! One of the best ways is to plant more trees. Trees help to stabilize the soil and prevent erosion. Another way is to practice sustainable farming. This means using farming methods that don't harm the land, like rotating crops and using less water. We can also build check dams and contour trenches to stop water from flowing too fast and washing away the soil.So guys, let's do our part to protect the land from becoming deserts! Plant trees, take care of animals, and farm in a sustainable way. Together, we can help control land desertification and make the world a better place for everyone!。

• ________ Organic farming is becoming more popular with some farmers and many _________ customers after these discoveries came out. Organic farming does not use any chemicals. There are many organic farming_________ methods for making the land healthy and productive. All of these methods try to produce good food and to keep the _____________and people’s ________. environment health
258180305@
Unit2 Chemical and organic farming
Unit2 Chemical and organic farming
新泰一中 逯晓菲
Before Class
Get Ready for the Class
• Number the paragraphs. • Form groups and find your group leader. • Speak as loudly as you can. • Don’t be shy; just have a try.
affect_____,_______ crops animals and _______ humans dieases ___________
fruit, vegetables and other food
by staying in the___________and ground underground _____________water for long

ResearchCrop Genetics and Breeding—ReviewAphanomyces euteiches :A Threat to Canadian Field PeaProductionLongfei Wu a ,Kan-Fa Chang b ,Robert L.Conner c ,Stephen Strelkov a ,Rudolph Fredua-Agyeman b ,Sheau-Fang Hwang b ,⇑,David Feindel baDepartment of Agricultural,Food and Nutritional Science,University of Alberta,Edmonton,AB T6G 2P5,Canada bCrop Diversification Center North,Alberta Agriculture and Forestry,Edmonton,AB T5Y 6H3,Canada cAgriculture and Agri-Food Canada,Morden Research and Development Centre,Morden,MB R6M 1Y5,Canadaa r t i c l e i n f o Article history:Received 2February 2018Revised 2May 2018Accepted 8June 2018Available online 17July 2018Keywords:Field peaAphanomyces euteiches Root rotPathogenicity variability Quantitative trait locia b s t r a c tField pea (Pisum sativum var. arvense L.) is an important legume crop around the world. It produces grains with high protein content and can improve the amount of available nitrogen in the soil. Aphanomyces root rot (ARR), caused by the soil-borne oomycete Aphanomyces euteiches D rechs. (A. euteiches ), is a major threat to pea production in many pea-growing regions including Canada; it can cause severe root damage, wilting, and considerable yield losses under wet soil conditions. Traditional disease manage-ment strategies, such as crop rotations and seed treatments, cannot fully prevent ARR under conditions conducive for the disease, due to the longevity of the pathogen oospores, which can infect field pea plants at any growth stage. The development of pea cultivars with partial resistance or tolerance to ARR may be a promising approach to analyze the variability and physiologic specialization of A. euteiches in field pea and to improve the management of this disease. As such, the detection of quantitative trait loci (QTL) for resistance is essential to field pea-breeding programs. In this paper, the pathogenic characteristics of A. euteiches are reviewed along with various ARR management strategies and the QTL associated with partial resistance to ARR.Ó 2018 THE AUTHORS. Published by Elsevier LTD on behalf of Chinese Academy of Engineering and Higher Education Press Limited Company. This is an open access article under the CC BY-NC-ND license1.IntroductionField pea (Pisum sativum var.arvense L.),along with common bean (Phaseolus vulgaris L.),faba bean (Vicia faba L.),soybean (Gly-cine max (L.)Merr.),chickpea (Cicer arietinum L.),and lentil (Lens culinaris Medik.),belongs to the family Fabaceae.The interaction between pea and Rhizobium bacteria leads to the formation of root nodules,which enable pea roots to fix nitrogen directly from the atmosphere,thereby benefiting production of the pea and subse-quent crops.Pea seeds have a high protein content,are rich in starch,dietary fiber,vitamins,minerals,and polyphenols,and provide a protein-rich food source for both humans and livestock [1].Garden peas are processed for canning or freezing by the food industry,while field pea is one of the most widely cultivated crops for human consumption and livestock feed on the Canadian Prairies,with an export market value of 1.2billion CAD in 2016[2].World grain pea production peaked in 1990at 1.66Â107t;by 2014,it had decreased by 5.5Â106t due to a reduction in pea cultivation in Europe [3,4].Since then,European pea cultivation has once again increased as a result of new Common Agricultural Policy (CAP)greening measures [5].Pea cultivation was introduced to Canada more than a century ago [6],first in limited areas in East-ern Canada in the late 1800s.In 1985,there were only 8.05Â104hm 2of field peas seeded in Canada.There was a significant increase in pea cultivation in North America (i.e.,Canada and the United States)starting in the 1990s.Because of its adaptation to cool climates and its nutritional value for human and livestock consumption,field pea has become increasingly popular as a cash crop to meet demand for the export market in Canada.By 2014,Canada had become the largest field pea producer in the world,which now accounts for 21%of global production [4].At present,Aphanomyces root rot (ARR)is one of the major limitations to pea production worldwide.This disease is caused by Aphanomyces euteiches Drechs.(A.euteiches ),which is distin-guished from most other soil-borne pathogens by the formation of thick-walled oospores [7].It can cause severe root damage at all growth stages of its host.The longevity of A.euteiches oospores,⇑Corresponding author.E-mail address:sheau-fang.hwang@gov.ab.ca (S.-F.Hwang).combined with the absence of fully resistant pea genotypes, makes the management of ARR difficult.This review describes pathogenic variability in A.euteiches,and the application of tradi-tional management strategies and partial resistance to control ARR infield pea.Pea root rot complex(PRRC)has been reported to be a serious problem infield pea production in Canada[8]and worldwide[9]. When root rot is severe,yield reduction can be as high as70% [10,11].A number of soil-borne pathogens have been reported to be involved in PRRC,including A.euteiches,Fusarium spp., Pythium spp.,Phytophthora spp.,and Rhizoctonia solani Kühn [12–15].Fusarium solani(Mart.)Sacc.(F.solani)was the most common causal agent of pea root rot worldwide[16].In addition to Fusarium spp.,A.euteiches has been reported to occur in certain countries in North America and Europe,as well as in Japan,Aus-tralia,and New Zealand[17].Yield losses due to infection by Pythium ultimum and A.euteiches were reported in the United States[18,19].An estimated loss of2.4Â104t offield pea caused by PRRC occurred in Southern Ontario in1983[10].F.avenaceum (Corda ex.Fr.)Sacc.was reported to be the main cause of Fusarium root rot in pea crops in Alberta and Manitoba,account-ing for as much as80%of the isolates collected fromfield samples [20,21].Hwang and Chang[22]reported that PRRC was prevalent in the Canadian province of Alberta.Tu[23]noted that the amount of damage tofield pea caused by Fusarium spp.is influ-enced by soil compaction,temperature,and moisture levels, which may also impact the relative prevalence of F.solani[16] and F.avenaceum[20].Infection by PRRC is associated with seed decay,damping-off, seedling blight,root rot,and wilt;however,the identity of the causal organisms cannot be determined solely by examining the symptoms[24].This increases the difficulty of predicting and controlling pea root rot in western Canada and elsewhere.Direct invasion of the seeds by any of the fungi involved in the PRRC complex,but most often by Pythium spp.,is usually the cause of seed decay[25,26],which results in a soft,mushy appearance of the seeds and in their rapid deterioration.Damping-off and seedling blight reduce seedling emergence and plant density, limit pea growth,delay canopy closure,and therefore increase weed competition.All of these factors may cause yield reductions [27].Root rot also restricts the transport of water and nutrients in infected roots,and reduces canopy density and the uniformity of crop maturity[28].Root rot may also destroy rhizobial nodules,leading to a reduction in nitrogenfixation in the roots[29].2.ARR caused by A.euteichesA.euteiches belongs to the class Oomycota(oomycetes),which comprises a large group of eukaryotes that includes the most diverse,important,and earliest-known water molds[30].Oomy-cetes resemble fungi in morphology(i.e.,mycelial growth)and many are parasitic.Unlike true fungi,oomycetes produce motile, biflagellate zoospores[30,31].Cytological and biochemical studies indicate additional differences that distinguish oomycetes from fungi[32–34].At the vegetative stage,the mycelia of oomycetes consist of a coenocytic thallus that remains diploid[33](Fig.1 (a)).The formation of haploid nuclei only occurs through meiosis for gamete formation.At this stage,fungal thalli produce septate cells,each of which carry one haploid nucleus.In addition,in con-trast to fungal cell walls,which are composed mainly of chitin (acetylglucosamine polymers),along with glucans,polysaccha-rides,mucopolysaccharides,waxes,and pigments,the cell walls of oomycetes contain cellulose,b-glucans and hydroxyproline, but no chitin[35].The genus Aphanomyces includes a number of water molds that are saprophytes or parasites offish,crayfish,and plants[36].There are about40described species of Aphanomyces[37].Most have a wide range of hosts belonging to different families,although there are a few exceptions such as A.cochlioides Drechs.,which only affects sugar beet(Beta vulgaris L.)[37]and A.iridis Ichitani et Tak.Kodama,which only affects iris(Iris spp.)[36].Although A. euteiches has a broad host range within the family Fabaceae,it causes the greatest economic damage to pea and lentil crops [38–40].This parasite has been isolated from pea,alfalfa(Medicago sativa L.),snap and red kidney bean(Proteus vulgaris L.),faba bean, red clover(Trifolium pratense L.),white clover(Trifolium repens L.), lentil,and several weed species[38,41].Nevertheless,its occur-rence and degree of pathogenicity may differ from one host to another.Pea-infecting strains and alfalfa-infecting strains of A. euteiches from the United States and France have been identified, and some strains can infect both pea and alfalfa[39,42,43].Papavi-zas and Ayers[38]reported that infection by A.euteiches caused large economic losses in pea and alfalfa crops in North America and Europe.The wide host range of A.euteiches,combined with its long-lived oospores,makes the management of ARR with crop rotation difficult.Since it wasfirst described by Jones and Drechsler[44]and extensively reviewed by Papavizas and Ayers[38], A.euteiches has been considered to be one of the most damaging soil-borne pathogens of legumes.At present,A.euteiches has been reported in all of the main pea cultivation regions of the world[17].In France,it affects pea crops in the northern regions of the country [41].In North America,it causes severe yield losses in the Great Lakes region in both Canada and the United States,as well as in the Northeastern[25]and the Pacific Northwest[45]regions of the United States.A high incidence and severity of pea root rot caused by A.euteiches was recently reported in Alberta[46].Yield losses caused by this parasite can be as high as86%in heavily infested peafields[47].2.1.Favorable conditionsSymptoms of ARR can develop within7–14days afterfirst infection,depending on soil moisture,temperature,and the concentration of oospores[38,47].High inoculum densities of A.euteiches increase the incidence and severity of ARR.Chan and Close[7]observed a positive correlation between the num-ber of oospores per100g of soil and root rot severity.Oospores can form germ tubes,which directly penetrate the cortex of the pea roots.Soil moisture levels influence the formation of sporangia and the release of zoospores,and allow theflagellated zoospores to travel to the plant roots in the moisturefilms sur-rounding soil particles[48,49].Zoospore infection also facilitates the leakage of metabolites from pea roots[50],which stimulates the germination of oospores and attracts more zoospores[9]. High rainfall favors ARR outbreaks,and only a short period is required for the completion of the infection process by A.euteiches[25].The minimum level of soil moisture needed for the initiation of ARR is about30%of the water-holding capacity of the soil[51,52].ARR may occur over the same wide soil-temperature range that is conducive for pea growth[25];however,the optimal tempera-tures for infection are about16°C,and20–28°C for disease devel-opment[53,54].High temperatures may accelerate pea root decay following infection by A.euteiches,since severe infection further limits water and nutrient movement withinfield peas[55].Gaulin et al.[56]reported that A.euteiches can infect legume hosts at any growth stage,while others have suggested that infection occurs most commonly at the seedling stage[57,58].L.Wu et al./Engineering4(2018)542–5515432.2.Life-cycle of A.euteichesThe life-cycle of A.euteiches includes both asexual and sexual stages,which allow for its efficient dissemination via zoospores and its survival as oospores during harsh winter conditions [41].The oospores are 18–25l m in diameter,have a thick protective wall,and contain energy reserves in the form of a large oil globule [9,38].They can survive in the soil for over ten years [47]and may be spread over long distances by the transportation of infested soil and/or infected plant residue [38].When adjacent to pea roots,the oospores germinate under con-ducive temperature and moisture conditions,and form either a mycelium or a zoosporangium.The zoosporangium,which forms as long tubes on the oospores,may release a large number of zoos-pores [59].The biflagellate motile zoospores are attracted to a suit-able host by chemical signals in the root exudates [60],and encyst within minutes on the rhizoplane (Fig.1(a)).The resulting cysts germinate and penetrate the host cortical cells within hours [38].Once an infection site has been established,coenocytic hyphae develop rapidly in the intercellular spaces of the host root tissue and the pathogen spreads from the roots to the stem (hypocotyls and epicotyls),eventually colonizing the entire root system.The infected roots become soft and water-soaked,and take on a honey-brown or blackish-brown coloration,which turns orange-brown or blackish-brown during the later stages of disease devel-opment (Fig.2(b)and (c)).Within a few days of infection,A.euteiches may enter its sexual stage with the formation and fusion of haploid antheridia and oogonia [59](Fig.1(a)and (d)).Subsequently,thick-walled oos-pores are formed,which ensure the long-term survival of the pathogen and serve as the primary source of inoculum for new infections in subsequent years [61](Fig.1(e)).The parasite may progress from first infection of the roots to formation of oospores in as few as 10–14days [62].The translocation of water and nutrients within infected plants can be restricted by severe root rot [63](Fig.2(a)and (f)).Infectedplants may become stunted during the early growth stages and then start to wilt,resulting in premature death [64](Fig.2(d)).Moreover,ARR may severely delay pea maturity,reduce pod size and seed number,and decrease seed quality [64](Fig.2(e)and (g)).2.3.Variability and physiological specialization in A.euteiches Information on pathogenic variability and physiologic speciali-zation in A.euteiches is limited.Given the absence of completely resistant or immune pea genotypes,it is difficult to create a differ-ential set to distinguish races,and the races identified by the limited differential genotypes may exhibit atypism [38].Nonethe-less,differences among isolates have been detected based on zoos-pore and oospore size,the time required for sporulation and the ability to produce zoospores,growth rate on culture media,and the production of pectinolytic and cellulolytic enzymes [38].Physiological specialization in A.euteiches was first examined by King and Bissonnette [65],who indicated that isolates of the parasite differed in their virulence patterns on various pea culti-vars in Minnesota.Carlson [55]tested ten isolates of A.euteiches ,which were isolated from infested soil from Minnesota,New York,and Wisconsin,by inoculating the root tips of tolerant and suscep-tible pea cultivars,and reported considerable differences in the ability of the isolates to infect plants and produce oospores.Vari-able virulence and growth characteristics on culture media were also observed among seven single-zoospore isolates obtained from germinated oospores [48].Beute and Lockwood [66]inoculated six differential cultivars with 15A.euteiches single-zoospore isolates,and identified two races based on their virulence on those pea cul-tivars (Table 1)[66–70].The two races displayed a different disease reaction pattern on the six pea cultivars,based on disease severity.Employing the same differentials as Beute and Lockwood [66],Sundheim and Wiggen [67]confirmed the existence of four physiological races of A.euteiches in a collection of 14isolates from four counties in Norway.Sundheim and Wiggen [67]evaluated resistance by counting the number of dead plants ten daysafterFig.1.Structures of A.euteiches .(a)Coenocytic hyphae with no septa;(b)encysted zoospore losing both flagella;(c)oogonium of A.euteiches ;(d)antheridium and oogonium of A.euteiches during the sexual stage;(e)thick-walled oospore for survival in unfavorable conditions.544L.Wu et al./Engineering 4(2018)542–551inoculation.The method of race identification described by Sund-heim and Wiggen [67]was questioned by Manning and Menzies [68],who suggested that the irreversibly wilted plants 10d after inoculation could not fully reflect the virulence spectrum of A.euteiches.The inconsistencies between these studies underscore the difficulties associated with race identification in A.euteiches .Malvick and Percich [69]developed a new differential set (con-sisting of the pea genotypes MN313,MN314,90-2079,WI-8904,Little Marvel,Saranac,and Early Gallatin)to evaluate pathogenic diversity among 114A.euteiches isolates from the United States (Table 1),and also examined genetic variation via random ampli-fied polymorphic DNA (RAPD)analysis.All isolates were patho-genic on one or more pea cultivars,and 18%and 14%were pathogenic on alfalfa (Saranac)and bean (Early Gallatin),respec-tively.Malvick and Percich [71]concluded that A.euteiches popula-tions were genotypically (based on the RAPD analysis)and phenotypically variable in the central and western United States.In a subsequent study,four virulence groups were identified,in which a disease severity of greater than 3.0(i.e.,>90%of the roots brown or yellow,but no symptoms present on the epicotyl or hypocotyl)was used as the threshold for a clear pathogenic inter-action [72].Fig.2.Symptoms of pea ARR caused by A.euteiches.(a)Yellowing and stunting of pea stems in the field;(b)comparison of healthy (left)and diseased (right)plants;(c)discoloration and water-soaking of diseased pea rootlets;(d)wilted pea plants in the field near harvest;(e)comparison of healthy (left)and diseased (right)pods;(f)Seedling blight in a low area of a field after heavy rainfall;(g)bleaching of leaflets and premature ripening of the pod.Table 1Studies on pathogenic variability and physiological specialization in A.euteiches isolates from pea using various sets of differential pea genotypes.MethodDifferential genotypesIdentified race/virulence type Isolate region Ref.Race identification Miragreen;Early Perfection;PI 175232;PI 169604;PI 180693;PI 166159Races 1and 2United States [66]Race identification Miragreen;Early Perfection;PI 175232;PI 169604;PI 180693;PI 166159Races 1–4Norway [67]Race identification Miragreen;Early Perfection;PI 175232;PI 169604;PI 180693;PI 166159Race 5New Zealand [68]Pathogenic variability MN313;MN314;90-2079;WI-8904;Little Marvel;Saranac;Early GallatinVirulence groups I–IV United States[69]Pathogenic variabilityBaccara;Capella;90-2131;MN313;552;PI 180693Virulence types I–XINorth America,Europe,and Oceania[70]L.Wu et al./Engineering 4(2018)542–551545Later,Wicker and Rouxel[70]examined109isolates of A.eute-iches from France,Denmark,Sweden,Norway,the United States, Canada,and New Zealand on another differential set(Baccara, Capella,90-2131,MN313,552,and PI180693)and identified11 virulence types(Table1).In that study,the isolates belonging to virulence type I,which caused severe ARR symptoms on all of the differentials,were predominant and the most aggressive. Wicker and Rouxel[70]also calculated a disease severity index (DSI)based on the mean of the individual disease severity ratings (0–5),and regarded a DSI<1as indicative of resistance.In a later study,Wicker et al.[17]indicated that the differential pea genotypes used by Malvick and Percich[69]were inadequate to distinguish French strains of A.euteiches.To more accurately evaluate the virulence of the pathogen from different countries, Wicker et al.[17]evaluated33pea lines and thefive differentials originally described by Wicker and Rouxel[70].The resistance detected in the differential pea genotypes in these studies has been used in the development of commercial pea cultivars with ARR resistance[17].Wu[73]conducted greenhouse screening of eight A.euteiches isolates from Alberta and Manitoba on the same differ-ential set as Wicker and Rouxel[70].Most strains were classified as virulence type I,although one strain was identified as virulence type III.Further testing of additional isolates from other Canadian regions with more differential breeding lines is still needed in order to better understand physiological specialization in this pathogen.2.4.Isolation of A.euteichesThe isolation of A.euteiches strains is difficult.Pea root and root-let samples easily slough off infected tissue into the soil[74]. Numerous fungi also interfere with the isolation of A.euteiches [75].Manning and Menzies[75]successfully isolated A.euteiches on potato dextrose agar(PDA)plates using soil baiting.To increase the isolation success rate,metalaxyl-benomyl-vancomycin(MBV) [25]medium has been widely used to isolate A.euteiches,since it suppresses the growth of Pythium spp.,Phytophthora spp.,and most bacteria.Wu[73]used both direct isolation from infected root samples and soil baiting.For direct isolation,root and soil samples were collected at2–3weeks after seeding,when roots were not yet com-pletely infected by PRRC.The soil samples were later used for pathogen baiting with susceptible pea cultivars[68].The tips were cut from water-soaked pea roots and examined under a micro-scope for the presence of oospores.The root tips were surface-sterilized in1%NaClO for30s,rinsed in sterilized water,and plated on MBV medium.However,A.euteiches was detected in <0.1%of the samples,based on the results of a real-time poly-merase chain reaction(PCR)assay described by Vandemark et al.[76].2.5.Inoculation methodsZoospores are the most common form of A.euteiches inoculum employed in greenhouse experiments[17,43,70,77–83],while oospore-based inoculum has also been used in both greenhouse andfield trials[38,73].The zoospore-based inoculum has been used widely for the detection of partial resistance to ARR infield pea[77–83].Zoospore inoculum is usually produced in a broth made from corn kernels,maltose-peptone,and oat(Avena sativa L.),or from pea seeds suspended in water,which are inoculated with A.euteiches and incubated for5–7d in the dark at room tem-perature[84].The resulting mycelial mats are placed in a mineral salt solution and aerated overnight to produce a zoospore suspen-sion of3Â105–8Â105zoospores per milliliter.The zoospores are usually used to precisely inoculate seven-day-old pea seedlings,before the seedlings are transplanted into pots in a green-house,with a determined zoospore concentration,thus eliminating the undesirable effect of nutrient substances in the media.Oospore inocula have been produced on autoclaved rolled oats with sand,cornmeal,and water.This substrate is inoculated with A.euteiches and incubated in the dark for30days at room temper-ature[38].Wu[73]modified this method by replacing cornmeal with oat grain.The grain-sand inocula were often used infield trials,as well as in greenhouse experiments,which need intensely infected disease conditions.Thygesen et al.[85]incubated A.euteiches in an oatmeal broth at20°C in the dark for4–8weeks; the broth was homogenized in a blender and thenfiltered and washed with a mineral salt solution.The suspension was mixed with sterilized sand,dried at room temperature,and stored at 4°C.The oospore suspension also provides a precise inoculation for both the pea seedlings and pea seeds,which could continuously release zoospores in a greenhouse experiment.3.Traditional disease managementARR has been recognized as one of the most damaging root diseases offield pea for almost a century[86].The options for management of this disease,however,are limited.Pea cultivars completely resistant to ARR are not available[25,87]and only partial resistance and/or tolerance has been reported in several studies[80,81,88].Some studies have focused on the efficacy of fungicidal seed treatments at the seedling stage,which have been shown to improve plant health[89,90].At present,the most widely recommended method to manage ARR is avoidance via crop rotation and evaluation of infestation levels in thefield prior to seeding[91].Biological control,including seed and soil treatments,has also shown promise at the experimental stage [9,92].3.1.Cultural practicesCrop rotation is one of the oldest and most fundamental meth-ods to manage diseases caused by soil-borne pathogens,although its effectiveness directly coincides with the length of rotation [93].A positive relationship exists between the frequency of pea crops and root rot severity[86].Rotation with non-host crops can therefore reduce the density of A.euteiches in the soil and thereby reduce the severity of ARR.Long-term crop rotations can reduce A.euteiches inoculum density in the soil,but they are not always effective in eradicating the disease[94].Nonetheless,the practicality and effectiveness of crop rotation as a method to manage ARR is questionable,because the oospores can survive for10–15years in the absence of a host[95].Furthermore,many alternative hosts,including chickpea,lentil,alfalfa,and weedy species,can sustain inoculum levels in the absence of pea[38]. Hossain et al.[96]recommended a crop rotation interval of6–8 years.Williams-Woodward et al.[97]examined the effect of oats as a rotation crop with pea,and observed that oat residues improved ARR suppression.Therefore,increased crop diversity may represent a good long-term strategy for disease management [98].Soil conditions can be suppressive or conducive to ARR[99]. Heyman et al.[100]observed a strong negative correlation between calcium concentration and disease development,which indicated that free calcium was a major variable in the degree of soil suppression of A.euteiches.Thisfinding led to the suggestion that calcium might play a role in the inhibition of zoospore produc-tion from the oospores[100].Residues from two plant families,the Brassicaceae—such as cabbage(Brassica oleracea L.),mustard(Brassica nigra L.),turnip546L.Wu et al./Engineering4(2018)542–551(Brassica rapa L.),and rapeseed(Brassica napus)[7,8,63,101–103]—and the Poaceae—such as oats,rye(Secale cereale L.),and maize (Zea mays L.)[8,97,104–108]—can reduce the severity of ARR.Soil compaction can exacerbate the development of ARR, causing pea yield losses as high as63%[107].In contrast,the yield of pea plots covered with oat shoots and residues increased by48% relative to plots planted without residues,suggesting that oat residues provide a promising method for the cultural control of pea ARR.Allmaras et al.[87]confirmed the effect of oats as a pre-crop in the suppression of ARR,and pointed out that excessive compaction related to tillage and traffic management may impair internal soil drainage and thus reduce the effectiveness of oat residues in controlling the disease.Field indexing by sampling soils to determine the A.euteiches inoculum potential can be an effective method to manage ARR of field pea prior to seeding.Studies have identified and distinguished heavily infestedfields from non-infested or lightly infestedfields under greenhouse conditions[109,110],and this method of prior land selection can be an economical and dependable practice for avoiding ARR[111].Real-time PCR analysis has also been used to measure populations of A.euteiches infield soil.Vandemark et al. [112]and Armstrong-Cho et al.[113]demonstrated that a positive relationship existed between ARR severity and the DNA concentra-tion of several isolates of A.euteiches in pea roots.3.2.Disease prediction and molecular detection of A.euteichesMolecular markers are useful tools for the identification of fungal and oomycete plant pathogens.The testing of soil or plant samples for the presence of A.euteiches DNA by PCR analysis with species-specific primers has been widely used[76].Chatterton et al.[46]and Armstrong-Cho et al.[113]detected A.euteiches in peafields in Alberta and Saskatchewan,respectively,based on a PCR assay.A number of commercial kits have also been used to identify A.euteiches efficiently[46,76,112].Nonetheless,informa-tion on the use of molecular markers for the identification of specific races or pathotypes of A.euteiches is still limited and preliminary.Malvick and Percich[69]conducted RAPD analyses to evaluate genotypic diversity among strains of A.euteiches in the United States,but none of the76polymorphic RAPD markers were associ-ated with pathogenic variation.In another study,the same researchers successfully distinguished one major group and two closely related minor groups in a collection of114isolates from four locations in the United States,based on a pathogenicity test offive pea genotypes and RAPD analysis[69].Sauvage et al. [111]used two sets of markers,136F/136R and11F/280R, to amplify different-sized PCR products from105isolates of A.euteiches.They demonstrated a close relationship between the quantity of soil inoculum and ARR severity.3.3.Seed and soil treatmentsCertain soil fungicides for ARR control are prohibited in some regions,including much of Europe[96].In addition,the cost and adverse environmental effects of treating the soil with chemicals makes this approach impractical and undesirable across the broad area over which pea crops are grown[114,115].Seed-coating treat-ments such as hymexazol can effectively improve seedling emer-gence[116].However,Tu[106]pointed out the limitations in the control of pea root rot using Captan(N-trichloromethylthio-4-cyclohexene-1,2-dicarboximide).Furthermore,A.euteiches is resis-tant to some of the fungicides that are registered for the control of other oomycetes.For example,metalaxyl is active against most oomycetes,but not against Aphanomyces.It is the main ingredient of the selective medium used to isolate A.euteiches[25].Neither the systemic acylalanine-type of oomycete fungicides,such as met-alaxyl,nor the ethyl phosphonates,such as fosetyl-Al or cymoxanil, effectively control ARR[117].Some chemicals effectively suppress A.euteiches under controlled conditions,but have limited benefi-cial effects infield trials[89,90].Tachigaren(hydroxyisoxazole or hymexazol)was reported to reduce root rot severity and increase yield under experimentalfield conditions[116];this compound is available commercially in Japan for the control of the Pythium and Aphanomyces diseases of sugar beets[117].The effectiveness of Tachigaren for the control of ARR,however,was variable in other studies[118–120].A recent study determined that Intego Solo (ethaboxam)(Valent,Guelph,ON,Canada),BAS516F,and BAS 720F reduced disease severity under greenhouse conditions,but not underfield conditions[73].At present,ethaboxam is the only fungicide registered for Pythium root rot control and the suppres-sion of seed rot caused by Phytophthora spp.and Aphanomyces spp.in legumes in Canada.3.4.Biological controlAntagonistic microorganisms applied to the seeds or soil may help to protect pea plants from infection by fungal and oomycete pathogens.The spores of arbuscular mycorrhizal(AM)fungi and some spore-forming bacteria,which were applied as seed coatings to control ARR in peafields,significantly suppressed the develop-ment of ARR in afield trial[121].The application of isothiocyanate, a compound produced by members of the Brassicaceae in shoot tis-sues,has also been shown to have potential for the management of ARR due to its toxic effects on A.euteiches under controlled condi-tions[96].Biocontrol and fungicide treatments are often integrated into seed treatments.Recent studies have demonstrated that some fun-gal and bacterial strains,such as Gliocladium roseum(Clonostachys rosea(Link)Schroers),Pseudomonasfluorescens(Flügge)Migula, and species involved in the Burkholderia cepacia(Palleroni and Holmes)Yabuuchi et plex,which are formulated for seed coat application in combination with a fungicide,improved seed-ling emergence infields infested with A.euteiches to a greater extent than treatments in which only a fungicide was applied [17,18,90].Xue[90]evaluated a seed treatment consisting of the fungal strain ACM941(Clonostachys rosea)and a fungicide(Thiram 75WP(thiram)or Apron FL(metalaxyl)),and found that a seed coating with ACM941+fungicide improved pea seed germination in an A.euteiches-infestedfield.AM fungi have also been proven to increase the seedling emergence of peas when inoculated with A.euteiches in greenhouse experiments,but they were not always effective in thefield[85,122].Several studies indicated that solar-ization was effective for the control of pea root rot in temperate regions,when used in combination with green manure crops,lower dosages of chemicals,or biological control organisms[123,124]. 4.Genetic resistance to A.euteiches4.1.Partial resistance to ARRGenetic resistance to ARR infield pea could be the most economical and effective strategy for managing this disease.A number of pea-breeding lines with partial resistance or tolerance to ARR have been developed,and are used to prevent yield losses in some pea-producing regions[78,79,88,125].Some differential pea genotypes,such as Capella,MN144,MN313,MN314, 90-2131,90-2079,552,and PI180693,have been reported to be partially resistant to certain races of A.euteiches[17,72,125].The differentials PI180693and552have drawn considerable attention due to their high level of stable partial resistance to ARR[17,126].L.Wu et al./Engineering4(2018)542–551547。

土地污染的原因英语作文Causes of Soil Pollution.Soil pollution is a significant environmental issue that is often overlooked despite its far-reaching impacts on human health and the ecosystem. The degradation of soil quality can be attributed to various anthropogenic activities, natural processes, and a combination of both. This article delves into the primary causes of soil pollution, highlighting the human and natural factors that contribute to this pressing environmental concern.Anthropogenic Causes:1. Industrial Activities: Industrialization is one of the primary culprits of soil pollution. Factories and manufacturing units release various toxic chemicals and heavy metals into the soil through effluents, waste disposal, and leaky pipelines. These contaminants accumulate in the soil, affecting its fertility andcontaminating groundwater resources.2. Agricultural Practices: Intensive agricultural practices, such as the excessive use of fertilizers and pesticides, contribute significantly to soil pollution. These chemicals accumulate in the soil, affecting its biological properties and reducing soil fertility. Additionally, monoculture practices, which involve the continuous cultivation of a single crop, lead to soil depletion of essential nutrients.3. Urbanization: The rapid growth of urban areas leads to soil pollution through various means. Construction activities, road development, and urban planning often involve the excavation and displacement of soil, leading to erosion and the mixing of contaminants into the soil. Furthermore, the disposal of solid waste in urban areas, especially when not managed properly, can lead to soil contamination.4. Mining Activities: Mining operations, especially those involving the extraction of ores, can lead to soilpollution. The excavation and processing of ores release toxic chemicals and heavy metals into the soil, affecting its quality and making it unsuitable for agricultural purposes.Natural Causes:1. Erosion: Natural processes, such as wind and water erosion, can contribute to soil pollution. Erosion causes the loss of topsoil, which contains essential nutrients and organic matter. When this topsoil is lost, it exposes subsoils that may be less fertile and more susceptible to pollution.2. Volcanic Activity: Volcanic eruptions can release ash and gases that contaminate the soil. These contaminants can affect soil fertility and make it unsuitable for agriculture. Additionally, volcanic activity can also lead to the deposition of ash and debris, which can smother plants and affect soil quality.3. Natural Disasters: Natural disasters such as floods,earthquakes, and tsunamis can contribute to soil pollution. These disasters can cause soil erosion, deposit contaminants, and disrupt the soil's natural structure, affecting its fertility and quality.Conclusion:Soil pollution is a complex environmental issue that requires a multifaceted approach to address. Anthropogenic activities, such as industrialization, agricultural practices, urbanization, and mining, are the primary culprits of soil pollution. However, natural processes such as erosion, volcanic activity, and natural disasters can also contribute to soil degradation. To mitigate soil pollution, it is crucial to adopt sustainable practices, improve waste management, promote soil conservation measures, and enforce strict environmental regulations. By doing so, we can ensure the health and fertility of oursoil resources, safeguarding them for future generations.。

99年改错The hunter-gatherer tribes that today live as our prehistoric 1.______human ancestors consume primarily a vegetable diet supplementing 2._____ with animal foods. An analysis of 58 societies of modem hunter- gatherers, including the Kung of southern Africa, revealed that onehalf emphasize gathering plant foods, one-third concentrate on fishingand only one-sixth are primarily hunters. Overall, two-thirdsand more of the hunter-gatherer’s calories come from plants. Detailed 3.______ studies of the Kung by the food scientists at the University ofLondon, showed that gathering is a more productive source of foodthan is hunting. An hour of hunting yields in average about 100 4.______ edible calories, as an hour of gathering produces 240. 5.______Plant foods provide for 60 percent to 80 percent of the Kung 6._______diet, and no one goes hungry when the hunt fails. Interestingly, ifthey escape fatal infections or accidents, these contemporaryaborigines live to old ages despite of the absence of medical care. 7._______ They experience no obesity, no middle-aged spread, little dentaldecay, no high blood pressure, on heart disease, and their bloodcholesterol levels are very low( about half of the average American 8._______ adult), if no one is suggesting what we return to an aboriginal life 9.________ style, we certainly could use their eating habits as a model for 10.________ healthier diet.1999年1. 答案：as →like2. 答案：supplementing →supplemented3. 答案：and →or4. 答案：in →on5. 答案：as →while / whereas6. 答案：删去for，或改成about7. 答案：删去第一个of8. 答案：half ∧→that9. 答案：if →While / Although / Though10. 答案：for ∧→a2000改错The grammatical words which play so large a part in Englishgrammar are for the most part sharply and obviously different 1._______ from the lexical words. A rough and ready difference which mayseem the most obvious is that grammatical words have“ lessmeaning”, but in fact some grammarians have called them 2._______ “empty” words as opposed in the “full” words of vocabul ary. 3.________ But this is a rather misled way of expressing the distinction. 4._________ Although a word like the is not the name of something as man is,it is very far away from being meaningless; there is a sharp 5._________ difference in m eaning between “man is vile and” “the man isvile”, yet the is the single vehicle of this difference in meaning. 6.________ Moreover, grammatical words differ considerably amongthemselves as the amount of meaning they have, even in the 7.________lexical sense. Another name for the grammatical words has been“little words”. But size is by no mean a good criterion for 8._________ distinguishing the grammatical words of English, when weconsider that we have lexical words as go, man, say, car. Apart 9.________from this, however, there is a good deal of truth in what somepeople say: we certainly do create a great number of obscurity 10.________ when we omit them. This is illustrated not only in the poetry ofRobert Browning but in the prose of telegrams and newspaper headlines.2000年1. 答案：删去the2. 答案：but →and/thus3. 答案：in →to4. 答案：misled →misleading5. 答案：删去away6. 答案：single →only7. 答案：as →in8. 答案：mean →means9. 答案：∧lexical →such 或在words后加such，或把改成like10. 答案：number →deal / amount2001改错During the early years of this century, wheat was seen as thevery lifeblood of Western Canada. People on city streets watchedthe yields and the price of wheat in almost as much feeling as if 1._______they were growers. The marketing of wheat became an increasing 2._______ favorite topic of conversation.War set the stage for the most dramatic events in marketingthe western crop. For years, farmers mistrusted speculative grainselling as carried on through the Winnipeg Grain Exchange.Wheat prices were generally low in the autumn, so farmers could 3._______not wait for markets to improve. It had happened too often thatthey sold their wheat soon shortly after harvest when farm debts 4.________ were coming due, just to see prices rising and speculators getting rich. 5._______ On various occasions, producer groups, asked firmer control, 6._______but the government had no wish to become involving, at 7.______least not until wartime when wheat prices threatened to runwild.Anxious to check inflation and rising life costs, the federal 8.______ government appointed a board of grain supervisors to deal withdeliveries from the crops of 1917 and 1918. Grain Exchangetrading was suspended, and farmers sold at prices fixed by theboard. To handle with the crop of 1919, the government appointed 9.______the first Canadian Wheat Board, with total authority to 10.______buy, sell, and set prices.2001年1. 答案：in →with2. 答案：increasing →increasingly3. 答案：so →but4. 答案：删去soon或shortly5. 答案：just →only6. 答案：asked ∧→for7. 答案：involving →involved8. 答案：life →living9. 答案：handle →deal 或删去with10. 答案：total →full/complete/absolute2002改错There are great impediments to the general use of a standard in pronunciation comparable to that existing in spelling (orthography). One is the fact that pronunciation is learnt “naturally” and unconsciously, and orthography is learnt1__________ deliberately and consciously. Large numbers of us, in fact, remain throughout our lives quite unconscious with what our speech 2._____________ sounds like when we speak out, and it often comes as a shock 3.__________when we firstly hear a recording of ourselves. It is not a voice we 4._________recognize at once, whereas our own handwriting is something which we almost always know. We begin the natural learning 5.__________of pronunciation long before we start learning to read or write, and in our early years we went on unconsciously imitating and 6.____________practicing the pronunciation of those around us for many more hours per every day than we ever have to spend learning even our 7.______________difficult English spelling. This is “natural”, therefore, that our 8.______________speech-sounds should be those of our immediate circle; after all, as we have seen, speech operates as a means of holding a community 9._______________and giving a sense of 'belonging'. We learn quite early to recognize a “stranger”, someone who speaks with an accent of a different community-perhaps only a few miles far. 10.________________2002年1. 答案：第二个and →while / whereas / but / yet2. 答案：with →of3. 答案：删去out4. 答案：firstly →first5. 答案：which →that6. 答案：went →go7. 答案：删去per或every8. 答案：This →It9. 答案：community ∧→together10. 答案：far →away2003改错Demographic indicators show that Americans in the postwarperiod were more eager than ever to establish families. They quicklybrought down the age at marriage for both men and women and broughtthe birth rate to a twentieth century height after more than a hundred (1)______ years of a steady decline, producing the “baby boom.” These young (2)_______ adults established a trend of early marriage and relatively largefamilies that Went for more than two decades and caused a major (3)_______but temporary reversal of long-term demographic patterns. Fromthe 1940S through the early 1960s, Americans married at a high rate (4)________ and at a younger age than their Europe counterparts.(5)________Less noted but equally more significant, the men and women on who (6)________ formed families between 1940 and 1960 nevertheless reduced the (7)________ divorce rate after a postwar peak; their marriages remained intact toa greater extent than did that of couples who married in earlier as well (8)________ as later decades. Since the United States maintained its dubious (9)___________ distinction of having the highest divorce rate in the world, thetemporary decline in divorce did not occur in the same extent in (10)___________ Europe. Contrary to fears of the experts, the role of breadwinner and homemaker was not abandoned.2003年1. 答案：height →high2. 答案：a steady decline →steady decline3. 答案：went^ for →on或把went改成lasted4. 答案：high →higher5. 答案：Europe →European6. 答案：删去more7. 答案：把nevertheless 改成also,thus或therefore8. 答案：that →those9. 答案：Since →Although / While/though10. 答案：in →to2004改错One of the most important non-legislative functions of the U.S Congressis the power to investigate. This power is usually delegated to committees - either standing committees, special committees set for a specific (1)________ purpose, or joint committees consisted of members of both houses. (2)________Investigations are held to gather information on the need forfuture legislation, to test the effectiveness of laws already passed,to inquire into the qualifications and performance of members andofficials of the other branches, and in rare occasions, to lay the (3)________ groundwork for impeachment proceedings. Frequently, committeesrely outside experts to assist in conducting investigative hearings (4)_________ and to make out detailed studies of issues. (5)_________There are important corollaries to the investigative power. Oneis the power to publicize investigations and its results. Most (6)_________ committee hearings are open to public and are reported (7)__________widely in the mass media. Congressional investigationsnevertheless represent one important tool available to lawmakers (8)__________ to inform the citizenry and to arouse public interests in national issues.(9)________Congressional committees also have the power to compeltestimony from unwilling witnesses, and to cite for contemptof Congress witnesses who refuse to testify and for perjurythese who give false testimony. (10)_________2004年1. 答案：set ^for →up2. 答案：consisted →consisting/composed3. 答案：in →on4. 答案：rely ^ outside →on5. 答案：删去out6. 答案：its →their7. 答案：^ public →the8. 答案：nevertheless →therefore / thus9. 答案：interests →interest10. 答案：these →those2005改错The University as BusinessA number of colleges and universities have announced steeptuition increases for next year much steeper than the current,very low, rate of inflation. They say the increases are needed becauseof a loss in value of university endowments heavily investing in common 1 stock. I am skeptical. A business firm chooses the price that maximizesits net revenues, irrespective fluctuations in income; and increasingly the 2 outlook of universities in the United States is indistinguishable from those of 3 business firms. The rise in tuitions may reflect the fact economic uncertainty 4 increases the demand for education. The biggest cost of beingin the school is foregoing income from a job (this is primarily a factor in 5graduate and professional-school tuition); the poor one's job prospects, 6 the more sense it makes to reallocate time from the job market to education,in order to make oneself more marketable.The ways which universities make themselves attractive to students 7 include soft majors, student evaluations of teachers, giving studentsa governance role, and eliminate required courses. 8 Sky-high tuitions have caused universities to regard their students as customers. Just as business firms sometimes collude to shorten the 9 rigors of competition, universities collude to minimize the cost to them of the athletes whom they recruit in order to stimulate alumni donations, so the best athletes now often bypass higher education in order to obtain salaries earlierfrom professional teams. And until they were stopped by the antitrust authorities, the Ivy League schools colluded to limit competition for the best students, by agreeing not to award scholarships on the basis of merit rather than purelyof need-just like business firms agreeing not to give discounts on their best 10 customer.2005年1. 答案：investing – invested2. 答案：irrespective ∧- of3. 答案：those – that4. 答案：fact ∧economic – that5. 答案：in the school －去掉the6. 答案：poor – poorer7. 答案：∧which －in或把which改成that, 或删去which8. 答案：eliminate – eliminating9. 答案：shorten – lessen/reduce/minimize/weaken10. 答案：discount on – discount to2006改错We use language primarily as a means of communication withother human beings. Each of us shares with the community in which welive a store of words and meanings as well as agreeing conventions as 1_______ to the way in which words should be arranged to convey a particular 2______ message: the English speaker has in his disposal vocabulary and a3_______set of grammatical rules which enables him to communicate his4______ thoughts and feelings, in a variety of styles, to the other English 5_______ speakers. His vocabulary, in particular, both that which he uses activelyand that which he recognizes, increases in size as he growsold as a result of education and experience. 6______ But, whether the language store is relatively small or large, the systemremains no more, than a psychological reality for tike inpidual, unlesshe has a means of expressing it in terms able to be seen by another 7_______ member of his linguistic community; he bas to give tile system aconcrete transmission form. We take it for granted rice’ two m ost8_______ common forms of transmission-by means of sounds produced by ourvocal organs (speech) or by visual signs (writing). And these are 9______ among most striking of human achievements. 10_______2006年1. 答案：agreeing – agreed2. 答案：∧words – these3. 答案：in his disposal – at his disposal.4. 答案：enables – enable5. 答案：the other English speakers – other English speakers6. 答案：old – older7. 答案：seen – understood8. 答案：删去it9. 答案：And – But/Yet/However/Nevertheless10. 答案：most – the most2007改错From what has been said, it must be clear that no one canmake very positive statements about how language originated.There is no material in any language today and in the earliest 1 __ _ records of ancient languages show us language in a new and 2 _ emerging state. It is often said, of course, that the language 3 _ ______ originated in cries of anger, fear, pain and pleasure, and the 4 _ necessary evidence is entirely lacking: there are no remotetribes, no ancient records, providing evidence ofa language with a large proportion of such cries 5 _ than we find in English. It is true that the absenceof such evidence does not disprove the theory, but in6_other grounds too the theory is not very attractive.People of all races and languages make rather similarnoises in return to pain or pleasure. The fact that7such noises are similar on the lips of Frenchmenand Malaysians whose languages are utterly different,serves to emphasize on the fundamental difference8________ between these noises and language proper. We maysay that the cries of pain or chortles of amusementare largely reflex actions, instinctive to large extent, 9whereas language proper does not consist of signsbut of these that have to be learnt and that are10________ wholly conventional.2007年1. 答案：and – or2. 答案：show后面添加that或把show改成showing3. 答案：删去the4. 答案：and – but/whereas/while5. 答案：large – larger6. 答案：in – on7. 答案：return – in response/reaction/answer8. 答案：删去on9. 答案：增加a10. 答案：these – those2008年改错The desire to use language as a sign of national identity is a very natural one，and in result language has played a 1__________prominent part in national moves．Men have often felt the need 2__________to cultivate a given language to show that they are distinctive 3____________from another race．whose hegemony they resent．At the time the 4.___________ United States split off from Britain，for example，there were proposals that independence should be linguistically accepted by 5.____________the use of a different language from those of Britain．6.____________There was even one proposal that Americans should adopt Hebrew．Others favoured the adoption of Greek，though，as one man put it，things would certainly be simpler for Americans if they stuck on to 7.____________English and made the British learn Greek．At the end，as everyone 8.___________ knows，the two countries adopted the practical and satisfactory solution of carrying with the same language as before．Since nearly two hundred years now，they have shown the 9.______________world that political independence and national identity can be 10.___________ complete without sacrificing the enormous mutual advantages of a common language．2008年1. 答案：in result--- in consequence2. 答案：moves---movements3. 答案：distinctive---distinct/different4. 答案：time ∧--- when5. 答案：accepted--- acknowledged/confirmed/realized6. 答案：those---that7. 答案：删去on8. 答案：At---In9. 答案：carry ∧with --- on10. 答案：Since---For2009年改错The previous section has shown how quickly a rhyme passesfrom one school child to the next and illustrates the further difference (1)_____ between shcool lore and nursery lore. In nursery lore a verse, learntin early childhood, is not usually passed on again when the little listener (2)_____has grown up, and has children of their own, or even grandchildren. (3)_____The period between learning a nursery rhyme and transmittingIt may be something from twenty to seventy years. With the playground (4)_____ lore, therefore, a rhyme may be excitedly passed on whtin the very hour (5)_____it is learnt; and in the general, it passes between children of the (6)_____same age, or nearly so, since it is uncommon for the difference in agebetween playmates to be more than five years. If therefore, a playgroundrhyme can be shown to have been currently for a hundred years, or (7)_____even just for fifty, it follows that it has been retransmitting overand over; very possibly it has passed along a chain of two or three (8)_____hundred young hearers and tellers, and the wonder is that it remains live (9)_____after so much handling, to let alone that it bears resemblance to the (10)____original wording.2009年1. 答案：the further--- a further2. 答案：when---until3. 答案：their---his4. 答案：something---anything5. 答案：therefore---however/nevertheless/yet6. 答案：删掉in the general中的the7. 答案：currently---current8. 答案：over and over ∧--- again9. 答案：live --- alive10. 答案：删掉to let alone中的to2010年改错So far as we can tell, all human languages are equally complete and perfect as instruments of communication: that is, every language appears to be as well equipped as any other to say the things its speakers want to say. It may or may not be appropriate to talk about primitive peoples or cultures, but that is another matter. Certainly, not all groups of people are equally competent in nuclear physics or psychology or the cultivation of rice or the engraving of Benares brass. But this is not the fault of their language. The Eskimos can speak about snow with a great deal more precision and subtlety than we can in English, but this is not because the Eskimo language (one of those sometimes miscalled ’primitive’) is inherently more precise and subtle than English. This example does not bring to light a defect in English, a show of unexpected ’primitiveness’. The position is simply and obviously that the Eskimos and the English live in different environments. The English language would be just as rich in terms for different kinds of snow, presumably, if the environments in which English was habitually used made such distinction important.Similarly, we have no reason to doubt that the Eskimo language could be as precise and subtle on the subject of motor manufacture or cricket if these topics for med part of the Eskimos’ life. For obvious historical reasons, Englishmen in the nineteenth century could not talk about motorcars with the minute discrimination which is possible today: cars were not a part of their culture. But they had a host of terms for horse-drawnvehicles which send us, puzzled, to a historical dictionary when we are reading Scott or Dickens. How many of us could distinguish between a chaise, a landau, a victoria, a brougham, a coupe, a gig, a diligence, a whisky, a calash, a tilbury, a carriole, a phaeton, and a clarence ?。