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2022-2023学年高二生物寒假作业（测试卷一）一、单项选择题：共13题，每题3分，共39分。
每题只有一个选项最符合题意。
1.下列关于种群数量特征的叙述,正确的是( )A.种群密度是最基本的种群数量特征,是指种群在单位面积或单位体积中的个体数B.出生率、死亡率、迁入率和迁出率不是决定种群密度变化的决定因素C.年龄组成为稳定型的,出生率大于死亡率D.处于稳定状态的生态系统各种生物的种群密度不会发生变化2.下列为种群数量特征的两个概念图，有关分析错误的是( )A.图1中预测种群数量未来变化趋势的主要依据是bB.图1中的c为种群最基本的数量特征C.图2中的丁与图1中的a表示的含义相同D.图2中丙为性别比例，主要通过影响出生率来间接影响种群密度3.下列关于种群密度调查的叙述,不合理的是( )A.草地中跳蝻的种群密度一般不采用样方法进行调查B.用标志重捕法调查某种动物的种群密度时,要保证标记物不能影响标记动物的正常生活C.用样方法调查植物的种群密度时,常用的取样方法有五点取样法和等距取样法D.与单子叶植物相比,样方法更适用于调查双子叶植物的种群密度4.科学工作者为了检测和预报某草原（2hm2）鼠害的发生情况，采用标志重捕法对田鼠种群数量进行调查，第一次捕捉了50只，标记之后放回，一段时间后，第二次捕捉了20只，其中被标记的个体有5只。
下列分析正确的是( )A.标记方法要适宜，颜色要鲜艳便于科学工作者能准确辨认B.田鼠种群的出生率等于死亡率时，是防治鼠害的最佳时期C.如果被标记的个体产生记忆导致第二次不易捕捉，则测定结果会偏大D.该地区田鼠的种群密度为200只/hm25.下列关于种群的说法，正确的是( )A.种群的年龄结构是指种群中各年龄期个体的数量，包括增长型、稳定型、衰退型B.种群K值的大小主要取决于出生率与死亡率的相对大小C.调查种群密度时可以采用样方法、标记重捕法、逐个计数法等估算法D.若种群的出生率大于死亡率、迁入率大于迁出率，种群数量可能呈“S”形增长6.如图表示不同条件下某种细菌种群数量变化模型。
2021年高一（准高二）历史暑假作业（1）含答案一、选择题(本大题共25小题，每题2分，共50分。
在每小题的四个选项中，只有一项是符合题目要求的。
)1、远古时期，传说神农氏“因天之时，分地之利，制耒耜，教民农作”，反映了这一时期（）A．人们以采集经济为主 B.社会经济处于渔猎阶段C．原始农业的出现 D.全体小农经济的产生2、下面图一到图二两则史料的变化可以直接用来论证（）A．我国古代农业经营方式的变化 B．我国古代农业耕作方式的变化C．我国古代经济结构的变化 D．我国古代手工业技术的进步3、“一方田，一头牛，老婆孩子热炕头”，是中国古代农民向往的理想生活。
这突出反映了小农经济怎样的特点（）A．封闭保守 B．精耕细作C．耕织结合 D．艰难脆弱4、右图为出土于河南安阳殷墟的牛骨刻辞，上面刻有“王大令众人曰协田”。
关于卜辞中“众人协田”所包含的信息，下列说法不正确的是（）A．耕作方式为集体协作B．小农经济形态已经出现C．统治者重视农业生产 D．其中的“众人”多为奴隶5、在传统农业社会中，人流、物流和信息流的运动半径很小。
下列解释不确切的是（）A．做到了“鸡犬之声相闻，老死不相往来”B．绝大多数人口生活在相对封闭的环境中C．土地是最重要的生产资料，居民流动性很小D．传统农业社会建立在自给自足的小农经济基础上6、史书中关于“共计一坯工力，过手七十二，方克成器”的记载直接反映了景德镇制瓷业中（）A.规模大，分工极细B.与传统官办手工工厂相比发生了质的变化C.机器生产形成并发展D.形成了雇用和被雇用的劳资关系7、宋代文人孟元老在《东京梦华录》中记载：“市井经纪之家……夜市直至三更尽，才五更又复开张。
……通晓不绝……盖都公私营干，夜深方归也。
”材料所反映出宋代城市商业的特点是（）A.坊市界限不复存在B.市分散在城中，形成街市C.实行整齐划一的方式制度D.宋代取消了商业活动的时间限制8、16世纪晚期，山东某地开始出现“地多烟草、木棉、转卖四方，五谷之利不及其半”的情况，这说明当时该地（）①农业经济衰退②农业结构发生变化③商品经济发展④农产品加工业兴起A．①② B．②③ C．③④ D．①③9、清朝前期的商人“以末致财，以本守之”的做法，对当时资本主义萌芽成长造成的最大影响是（）A.资金短缺B.市场狭小C.劳动力缺乏D.原料不足10、宋代人口有1亿，耕地面积5．6亿亩；鸦片战争前，清代人口达到4亿，耕地只有11～12亿亩。
太原市第二实验中学校2022-2023学年高二年级寒假作业英语（一）高二英语备课组一．用括号内单词的正确形式填空1. The president said it was a great opportunity to teach kids about the ________ (elect).2. I don't have anything ________ (suit) to wear for the coming of age party.3. He opened his lunch box and poured in the hot water, and then the delicious smell ______(instant) filled the air.4. ________ (library) are trained experts who can match the right book to the right teen, whether he or she is a struggling reader, an English language learner, or disabled.5. In ________(conclude), I would like to thank everyone who helped me to adapt to new school life.6. When you face a difficulty, just stand back and look ________（objective）at the problem at first.7. It would be crazy to spend so much money on expensive ________（item）such as world-famous brand bags and perfumes.8. You should be aware that how you manage your _______ (financial) can make a big impact on your future life.9. Taking time to ________ ( investment) in yourself can be one of the most profitable decisions you'll ever make.10. Though Anne is from one of the most remote ________(district) of the south of Scotland, she never gives up pursuing her dance dream.二．用方框内短语的适当形式填空1. You've got to ________________ yourself, or you'll never succeed.2. Johnny's friendliness was ________________ his brother's rude behaviour.3. Every week I ________________ a few pounds for a new smartphone.4. We want to ensure that help is ________________ for all children suffering from mental illness.5. Some people who live in the undeveloped regions of the world even ________________ clean water.6. After the disaster, we ________________ by donating money and they felt grateful for that.7. He tried to stay ________________ his emotions. However, it's easier said than done.8. Try to be in ________________, instead of focusing so much on what the future may bring.9. ________________ a credit card means you've reached your credit limit and no longer have additional credit to use that card.10.Have you decided to move the family to Alaska for a new job? Don't I _______ _______ ______ on the matter?I am a college student now!三．阅读理解AJust over a year ago, my iPhone was picked. My first thought was to replace it. But I stopped myself and asked a question: Does owning a smartphone make my life better, or worse? I decided to try living for a time without a smartphone. So I bought an old, $30 flip phone and began my post-smartphone life.One day after I made the switch, my wife, daughter and I were in Washington visiting a museum. By afternoon, I started acting like a true addict. I used my wife's smartphone to check Gmail. The initial rush of seeing so many unread emails was spoiled ( 破坏) by a work-related message. For the next half-hour or so, I walked around thinking about that message instead of being present at the museum. I was physically there, but my mind was focused on work.The most immediate advantage of not owning a smartphone, I quickly learned, is the ability to immerse( 沉浸) yourself in social situations. Without a smartphone to look at, you don't have much of a choice but to be present, and other people — whether it's a colleague ( 同事) or a stranger on social media — can't enter your life easily at inconvenient times. So I made my short-term experiment permanent.Do I miss Google Maps? Kind of, but I've also discovered that not having it makes driving safer. I now check a map before I leave the house and write down basic directions. This keeps me focused on the road rather than the phone. If I get lost, it's nice to ask people for directions. What about Uber and Lyft? Not having them has encouraged me to ride my bike more, which has been great for my health and saved me hundreds of dollars. On the subject of money: My phone bill is now down to $30 a month. I have no data plan, no expensive phone to make payments on, no apps to buy.1. Why did the author buy the old phone?A. To save money.B. To reduce the risk of losing it.C. To break his smartphone addiction.D. To experience a smartphone-free life.2. What happened to the author at the museum that afternoon?A. He couldn't help accessing the Internet.B. He couldn't send his work-related email.C. He was urged to handle work immediately.D. He was prevented from destroying a work of art.3. What is the last paragraph mainly about?A. The disadvantages of Google Maps.B. The functions of three different apps.C. The benefits of not using a smartphone.D. The difficulties of not having a smartphone.BWhen you think of a national park, you generally picture fresh air and wild animals, right? Well, now you're going to have to add tea shops and something called “the Underground” to your definition (定义), because London, England has signed up to be the first “National Park City.”London was founded by the Romans around 2, 000 years ago and people have continually lived there since then. In all that time, however, nobody had the idea to replace all the parks with big box stores or high buildings, which means London already has a much lower urban density (密度) than most of the world's cities. Nowadays about a third of the city is green space.In July 2019, London announced its willingness to become the world's first National Park City. Now the city is moving toward the goal of achieving 50% green space by the year 2050 by connecting and increasing public parks, greening unused parking lots and the private yards of existing and new houses, and fixing some green roofs on existing buildings.“Encouraged by the aims and values of our rural (乡村的) national parks, the London National Park City is basically about making life better in the capital through both small everyday things and long - term thinking,”Daniel Raven-Ellison, who began the movement to make London a National Park City six years ago, said. “We've been doing that in London for centuries, which is why London is so green.” It's about going further to make the city greener, healthier and wilder; making the city richer in wildlife.London will have a much easier job achieving this type of green transformation ( 转变 ) than more densely-urbanized cities like Paris and New York, which have 10% and 27% green space, respectively. But that doesn't mean it's not possible — the National Park City Foundation hopes to include 25 more cities in addition to London by the year 2025. Glasgow, Scotland and Newcastle upon Tyne in northeast England are both considering becoming National Park Cities.4. What makes London more likely to become a National Park City than other cities?A. Its smaller population.B. Its locals' requirements.C. Its government's strict law.D. Its wider area of green space.5. What does Daniel try to talk about in the fourth paragraph?A. The values of newly-founded parks.B. The importance of his movement.C. The influence of green space on cities.D. The preparation for setting up a movement.6. What would be the best title for the text?A. London is leading the world in park constructionB. London becomes the world's first National Park CityC. London is listed as the world's most-visited cityD. London has built the world's first underground parkCWhen someone asks me what I do first thing in the morning I feel ashamed. Then, I have to shamefully admit that I turn my alarm off on my phone and scroll (滚屏) through WeChat. Before I've even had the chance to brush my teeth or wash my face I'm already right away attracted by whatever people are doing online. And I know it needs to change.But the last time I was asked this question was about two months ago and have I changed my ways? Not even a little bit. We all know how unproductive social media can be. So why is it so easy to get addicted to (沉溺于) a huge mass of pretty pictures, and funny behavior and ideas? And why is it so hard to change? Lisa Lewis, a doctor in Brookline tells me the answer is simple. “It's because the point of these apps is to keep you looking,” she says. “They want you to buy, and get you to follow and like. Their only purpose is to win your attention.”She says you must have a purpose when it comes to using any social media apps. “Don't just go on and scroll,” she explains. “Just like you wouldn't walk up to the refrigera tor and stare at what's inside for no reason, don't do the same with social media.” If social media is reducing your productivity and overall health, Lewis offers these steps:First, set a goal whenever you use a social media app. If you use WeChat to get inspiration to exercise, do that and then get off it. Next, you can use a timer. These days you can set a timer for how many hours a day youspend on social media. Set it and stick to it. And finally, you can create a prize to strengthen the behavior. When you set that timer and stick to it, positively strengthen the behavior with anything from tasty food to things you've been eyeing on Amazon.7. What can we say about the author according to Paragraph 1?A. She is shy about answering others' questions online.B. She cares little about other people's life.C. She works busily early in the morning.D. She is a heavy user of social media.8. Why is it difficult to beat the addiction mentioned in Paragraph 2 according to Lewis?A. The apps are aimed at attracting users.B. Social media are a good way to kill time.C. People want to communicate with friends.D. Online information is key to most people's life.9. Why does Lewis mention the refrigerator?A. To show how attractive social media could be.B. To discuss why social media reduce productivity.C. To explain one should use social media when necessary.D. To prove some content of social media is useful.10. What does the underlined part “the behavior” refer to?A. Drawing inspiration from social media.B. Using social media according to a timer.C. Trying to save money when shopping online.D. Learning to pay no attention to things you badly want.DWhen is a kid not a kid anymore? If you asked my 12-year-old daughter, the magical age would be 13, when you can no longer be considered a “child.” If you asked my 15-year-old niece, the age would be 16, when she will be able to drive a car and get an after-school job. According to the U. S. government, a child officially becomes an adult when they turn 18. That's when they can vote. But even though an 18-year-old starts paying taxes, the government does not consider that person mature enough to buy a beer. Still, even a kid who can buy a beer is not old enough to rent a car.Scientists have learned from a new study that when kids are around 18, their prefrontal cortex, which helps control impulses ( 冲动), solve problems, and organize behavior, is only halfway developed. That's not to say that kids in their late teens and early 20s can't take on these tasks, but it means that it's harder for them to do so — at least until around age 25 or so when this area of the brain fully develops.“What we're really saying is that to have a definition (定义) of when you move from childhood to adulthood looks absurd,” Peter Jones from the University of Cambridge said. “It's a much more nuanced (微妙的) change that takes place over thirty years.”This isn't a news flash for parents who have watched their teens take crazy risks while seeming unable to get their lives together until they're older. But this information throws new light on the way kids without as much support are treated. In the foster (寄养的) care system, once a child turns 18, he can no longer receivestate-backed support. And many people think this is too early for a teen to be on his own, especially a teen who has experienced a painful childhood. Because of this, some foster care advocates (提倡者) think it makes more sense for 25 to be the new legal age of adulthood.11. What does the author want to show us in Paragraph 1?A. Different age groups have different needs.B. Becoming an adult means you can do a lot of things.C. People have different opinions on becoming an adult.D. Children need to learn basic life skills to become an adult.12. What might be the purpose of the study?A. To explain why teenagers are at risk.B. To suggest a way of helping teenagers develop.C. To explore the characteristics of different age groups.D. To discover when the human brain is fully developed.13. What does the underlined word “absurd” in Paragraph 3 probably mean?A. Impossible.B. Invaluable.C. Unreasonable.D. Uninteresting.14. What influence may the study have?A. It may inspire teens to be independent.B. It may allow a 20-year-old to get government support.C. It may drive the government to protect the foster care system.D. It may encourage parents to stop supporting their children at college.四．七选五The age of majority is the age that children become adults by law. This means that they are legally in control of their own actions and decisions. 1. ________ When used this way, the word “majority” means having the necessary number of years to be considered an adult. The opposite is “minority”, which means bein g a minor or child.2. ________ The law in a given place may never actually use the words “age of majority”. The age of majority is a legally fixed age and idea of adulthood which is different in different places. It may not match the actual maturity of a person's body or mind. The age of majority is 18 in most places.3. ________ Once a person reaches the age of majority, there are some things they can do that they could not do before. These may include voting, buying or drinking alcohol and driving cars on public roads. The ages when these things can be done are different.4. ________Even after a person reaches the age of majority, they cannot do whatever they want to immediately. 5.________ For example, the youngest a person is allowed to purchase alcohol is 21 in all U. S. states even though the age of majority is 18 in most states. The age of majority in the Republic of Ireland is 18, but a person must be over 21 years old to stand for election.五．完形填空You could say young Moziah Bridges has a gift for fashion, but it's more than that. He was born in Tennessee on November 13, 2001. When he was very young, he traded bow ties for candies in the school playground. However, Moziah's 1 fashion sense led him to home in on (集中精力于) his gift for 2 , and he started his own company at the age of 9. What he loved most were bow ties. But the 3 was that he felt that none of his bow ties attracted young people. Thus, the next step for Moziah was to 4 ties that are suitable for the young. He asked his grandmother to teach him how to sew ( 缝纫) and worked 5 to improve. As a result, Mo's Bowswas given to the world. The colorful, handmade ties quickly achieved 6 on major networks. When discussing his creativity and inspiration, Moziah said that designing a colorful bow tie was just part of his 7 of making the world a fun and happier place.The Mo's Bows website is sweet and it has started to sell other products, such as pocket squares and T-shirts. There's even a guide suggesting how to 8 tie a Mo's Bow, which is certainly something that men of all ages can 9 .Moziah is also best known for having 10 on the NBC reality TV series “Shark Tank” at the age of 11, increasing the 11 and popularity of his products and he has earned over $165,000 from his business. The designer owes (把……归功于) all of his 12 to h is grandmother, because, as Moziah says, “She13 me to be the best.”Recently, Moziah sold his Go Mo bow tie and 14 $1, 600 to give to Glenview Summer Camp. That money was enough to 15 the camp costs for 10 kids, and this is an activity Moziah hopes to make a tradition. Moziah's next plan is to help more people in need. This young man certainly has big things ahead!1. A. doubtful B. terrible C. strange D. strong2. A. staying up B. dressing up C. cleaning up D. cheering up3. A. reason B. worry C. problem D. plan4. A. predict B. collect C. accept D. create5. A. tirelessly B. carelessly C. helplessly D. hopelessly6. A. independence B. balance C. popularity D. protection7. A. story B. research C. dream D. training8. A. necessarily B. properly C. frequently D. completely9. A. get through B. work out C. throw away D. learn from10. A. appeared B. served C. grown D. checked11. A. flow B. quality C. costs D. sales12. A. politeness B. survival C. success D. gift13. A. follows B. considers C. advises D. pushes14. A. borrowed B. raised C. lost D. demanded15. A. reduce B. change C. cover D. increase六．语法填空The relationship between children and their parents is the most important one in a child's life, 1. ________ often lasts well into adulthood. This relationship changes 2. ________ (great) as teenagers need increased independence from their family. With increased independence comes the possibility of increased risk, and teens need parents to help them rise to the challenges that adolescence presents. Though some 3. ________ (argument) between teenagers and their parents are normal, teenagers still depend on parents to provide support and help.Just as close parent-child relationships are connected with the 4. ________ (health) development of teenagers, positive parenting behaviors are connected with increased parent-child closeness. Parenting a teenager differs 5.________ parenting a younger child. As children grow, parenting changes from making decisions for younger children to helping teenagers make decisions on 6. ________ (they) own. Parents can provide needed support 7.________ (help) their teenagers understand how their choices can influence their health and well-being. Although friends become more important in the lives of teenagers, 8. ________ (influence) their dressing styles, certain behaviors and social life, parents still play 9. ________ important role. They help shape their educational plans, social values and world view.Developing a positive and strong parent-teenager relationship 10. ________ (do) good to teenagers. Positive parent-child relationships contribute to higher levels of self-esteem (自尊), happiness and kindness, and also reduce their physical and mental pains.七．翻译句子1. 明年的这个时候，你正坐在办公室里和你的同事一起工作。
一阅读理解（共两节，满分30分）第一节（共10小题; 每小题2分，满分20分）AAnne is six years older than me. Growing up, we were very poor, and my mother worked evenings at a factory in a small town. Not seeing my mother much, Anne looked after me and my younger sister. During those hard years, Anne was always there for me, not only as a big sister, but as a mother and my best friend.When I was seventeen and had no money, I thought my only chance of going to college was if I could win a scholarship. I had an important interview for such an award. Anne at that time was struggling, surviving on a part-time job as she put herself through the local munity college after serving in the army. I told her of my interview. I asked her advice on what to wear and showed her my best outfit (装束) and how I planned to be careful, how I sat so that the hole in the bottom of my shoes would not be seen, but I wasn’t sure what I would do if it rained.Anne suggested that we go shopping, and we took the bus to the JCPenney store. We found a beautiful pair of leather shoes on sale. She told me to try them on, but I thought it was just for fun as neither of us had ever owned anything that expensive before. But Anne handed me the boxed shoes and said, “Here, I’ll buy these for you.”“But . . .” was all I could say.“You deserve them,” she replied. “This interview is important. I want to see you get that scholarship.”I was speechless as I knew this was a lot of money for her, and she would probably have to eat nothing but noodles for at least a month.I went to the interview and crossed my legs so that my beautiful new shoes shone with pride. I won the scholarship and became an engineer. Although they were nice leather everyday shoes, I didn’t wear them much because they were so special. Now, after 20 years have passed, I still have that pair of shoes with me, and I just wear them on those occasions when I need to feel special.1. When the author was 17, Anne _____.A. was serving in the armyB. was continuing her studyC. was a salesgirl at the JCPenney storeD. was working in a small pany2. The author went to the interview _____.A. acpanied by AnneB. wearing a pair of worn shoesC. with confidenceD. with great anxiety3. What would be the best title for the passage?A. An important interviewB. A special pair of new shoesC. Memories of poor childhoodD. Lifelong gratitude to a friendBLooking good, feeling goodBorn to a model mom and a suit maker dad, fashion was actually in my blood.I always had a strong desire to dress in a certain way and to stand out from the crowd.Imademy own toys whenI was a young child and sewed my first skirt at just 10 years old.Afriend’s mother took one look at my skirt and told me that I should be a patternmaker. In high school I started making my own clothes, mostly changing other things because I never liked anything how it was when I bought it. During the last two years of school, I worked part-time for a small business that made hand-painted silk clothingand bags. The owner became the teacher who got me into design in the first place. Another useful bit of work experience then came when I worked at a showroom during fashion week andfound it very exciting. From there I worked at a top clothing store while I got my business started.For my business I started out with the idea that everything I did would be hand-made and one-of-a-kind, specially made for one individual who hopefully had the same tastes as me. Every morning I jumped out of bed,went to my studio and worked on my projects. This just showed how enthusiastic I felt about my work. And at night I even dreamed of new designs!Fashion design is functional art. What I mean is that it’s something close to you and something you can touch and feel, and actually interact with. My advice to any young person who wants to be a fashion designer is to get the basic skills early on, such as sewing and pattern-making. Even if you end up specializing, it’s really important to understand all aspects of design in order to make high-quality clothes.Also, if you dream of having your own clothing line, the best thing to do is start wearing your clothes. You have to try and do this because that’s the way you’re going to develop something that’s all yours andunlike anyone else’s. I pas sionately believe that the right clothing can make people feel better and give them more confidence.4. When the author was in high school, she ______.A. wore the latest fashionsB.was fondofhand-painted clothingC. began to make clothes on her ownD. dressed in the same way as her classmates5. What does the underlined word “functional” in Paragraph 4 probably mean?A. Practical.B. Standard.C. Decorative.D. plex.6. What advice does the author give to those who want to be fashion designers?A. Creating basic designs in high school.B. Wearinghigh-quality clothes all the time.C. Looking at what their friends are wearing.D. Deciding what is unique about their clothes.7. According to the author, well-designed clothes _______.A.cost people a lot of moneyB.bring people great successC. provide people with popular tasteD. helppeoplefeel sure ofthemselves第二节（共5小题；每小题2分，共10分）根据短文内容，从短文后的七个选项中选出能填入空白处的最佳选项。
得夺市安庆阳光实验学校高二册 Units1Ⅰ.单词拼写1．Children must be taught to see things in a ______(科学的) way. 2．After ______(毕业) from college, he determined to settle in the country.3．Do they ______(庆祝) Christmas in that country?4．He has done a good deal of ______(研究) on that subject.5．She ______(预言) that he would marry a doctor.6．It is natural that children are ______(好奇的) about everything around.7．I had no ______(耐心) to hear your complaints again.8．He is such an ______(有才智的) student that we all like him.9．______(明显地), he has no intention to help us out.10．You must have ______(误会) her! Ellie would never say anything like that.[答案]1．scientific 2.graduating/graduation 3.celebrate/observe 4．research 5.predicted 6.curious 7.patience8．intelligent 9.Obviously 10.misunderstoodⅠ.完成句子(湖北专用)1．My sister ____________(结婚) to a rich man in 2004.2．Let’s go there together, ____________(好吗)?3．The sweater is too dear; I ____________(买不起) it.4．They ____________(禁不住笑了) when they heard this story.5．It was four years later that the business of his company really ____________(腾飞)．6．____________(根据……所说) George, she’s a great player.(according) 7．____________(结果), they saved 90% of the trees in the forest.(result) 8．This song ____________(使我想起) the days when we weretogether.(remind)9．I have nothing to ____________(补充) my earlier statement.(add) 10．Does the quality of teaching ____________(取决于) class size？(depend)[答案]1．got married 2.shall we 3.can’t afford to buy4．couldn’t help laughing 5.took off 6.According to7．As a result 8.reminds me of 9.add to10．depend onⅡ.单项填空1．It ______ unusual courage and determination to make the break with his family.A. tookB. neededC. spentD. shared2．—Jane loves her boyfriend Peter very much.—Yes, she would ______ him a good wife.A. makeB. sendC. getD. marry3．Don’t be too ______ about things you are not supposed to know. A. strange B. amusingC. curiousD. conscious4．I’m determined to work hard at all my lessons until I ______.A. get my goalB. reach my hopeC. reach my goalD. arrive at my plan5．My daughter, ______ a nice young doctor two years ago, will get married next month.A. got engaged toB. got engaged inC. engaged toD. engaged in6．It was in the lab ______ was in the charge of Professor Smith ______ the experiment was carried out.A. that; whereB. where; thatC. that; thatD. that; which7．It has been raining every day so far. I hope tomorrow ______ fine.A. turns toB. turns upC. turns inD. turns out8．She was wearing black high－heeled shoes that ______ her skirt and jacket.A. suited B. fitC. matchedD. compared9．The first international peace park, which crosses the boundary ______ the United States and Canada meet, is called Waterton－Glacier International Peace Park.A. whereB. thatC. whichD. when10．If you are at all worried about your health, you should ______ medical advice.A. searchB. seekC. giveD. receive11．He went to the airport to meet his favorite film star, only ______ that she had left.A. to tellB. tellingC. to be toldD. being told12．—______ if we move the picture over there? Do you think it’ll look better?—I don’t think so.A. HowB. WhatC. AsD. Even13．He is said ______ the station already when the policeman arrived.A. to leaveB. to have leftC. to have been leftD. to be leaving14．He has written three books on computer networking, ______ one became a best－seller and was published in twelve languages.A. in whichB. in themC. of whichD. of them15．(2010·安徽师大附中摸底)Mr. Green has two sons, one of ______ working as a bus driver now.A. whoB. whomC. themD. whose[答案]1．A。
2013-2014学年高二数学寒假作业1一、填空题。
（共70分）1．若错误！未找到引用源。
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都为锐角,则错误！未找到引用源。
=__________．2．已知存在实数a 满足 2ab a ab >> ，则实数b 的取值范围为__________．3．设{}n a 是正项数列，其前n 项和n S 满足：4(1)(3)n n n S a a =-+,则n a =__________． 4. 已知条件错误！未找到引用源。
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是错误！未找到引用源。
的充分不必要条件，则错误！未找到引用源。
的取值范围是__________．5.已知关于x 的不等式 x + 1x + a < 2的解集为P ，若1∉P ，则实数a 的取值范围为__________．6．对一切实数x ，不等式01||2≥++x a x 恒成立，则实数a 的取值范围是__________． 7．已知错误！未找到引用源。
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都是单位向量，且错误！未找到引用源。
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内部两点，且满足错误！未找到引用源。
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的面积为__________． 9．已知a ，b 均为单位向量．若∣a ＋2b ∣＝7，则向量a ，b 的夹角等于 ▲ ．10、已知关于x 的方程1+=ax x 有一个负根，但没有正根，则实数a 的取值范围是__________． 11.已知实数,x y 满足153x y +≤，则2z x y =+的最小值是__________．12．圆心在错误！未找到引用源。
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高二年级语文假期作业一、（共30分，每小题3分）1．下列词语中加点的字的读音完全正确的一组是（）A．估量（liàng）携（xié）手奚（xī）落浅尝辄（zhé）止B．束（shù）缚端倪（ní）诺（rùo）言百折不挠（ráo）C．模（mú）样镣（liáo）铐赎（shú）罪梦寐（mèi）以求D．气馁（něi）迥（jiŏng）然不惮（dàn）卓（zhúo）有成效2.下列词语中书写完全正确的一组是（）A．污蔑纷繁芜杂安之若素义愤填赝B．蜿蜒平心而论至理名言汹涌澎湃C．谛造骇人听闻坚忍不拔衷心喜悦D．匿迹民不聊生永保生机没精打彩3．下列词语解释全都正确的一组是（）A．袅娜(柔美的样子) 过犹不及（过头或不够都不好）风致（美的姿态）闻过则喜（听到以后就感到高兴）B．遐（远）想纤延顾步(眷顾多情的样子)戮力（合力）同心进退维谷（比喻困境）C．眉黛（就是眉毛）道听途说（在道路上听到并传说）道歉（表示歉意）能说会道（善于言辞、很会说话）D．敛裾（提一提裙子）剑拔弩张（拔出刀剑、把箭射出）张榜（贴出文告）虚张声势（假装、夸大自己的气势）4、下列各句中加点的成语使用正确的一项是：（）A．青年人风华正茂，思维敏捷，接受新事物快，有着巨大的创造活力。
B．神舟5号宇宙飞船在完成飞行试验之后成功着陆了，广大科技人员无不欢欣鼓舞、弹冠相庆。
C．奶奶虽年事已高，但仍精神饱满，坐在椅子上夸夸其谈。
D．在“美化环境有我一份”活动中，许多单位的干部都倾巢而出，参加卫生大扫除5．依次填入下列各句横线处的词语，恰当的一组是（）①由于剩余价值的发现，这里就豁然开朗了，而先前无论资产阶级经济学家或社会主义批评家所做的一切都只是在黑暗中＿＿＿＿＿。
②今天我们在这里集会，就是要把这＿＿＿＿＿的情况公诸于众。
③本世纪下半叶，中国人民在党的领导下又为实现国家的繁荣富强，经过艰辛的探索，＿＿＿＿＿成功地走上了建设有中国特色社会主义的正确道路。
ACD 1A1B1C1D P（第13题）高二数学理科暑假作业（1）班级__________姓名__________学号__________一、填空题1．若“x ∈[2,5]或x ∈(－∞，1)∪(4，＋∞)”是假命题，则x 的范围是____________．2．命题“若△ABC 不是等腰三角形,则它的任何两个内角不相等”的逆否命题是_______________． 3．设甲、乙、丙是三个命题，如果甲是乙的必要条件，丙是乙的充分条件但不是乙的必要条件，则丙是甲的____________条件． 4．有下列四个命题：①“全等三角形的面积相等”的否命题； ②若a 2＋b 2＝0，则a ，b 全为0；③命题“若m ≤1，则x 2－2x ＋m ＝0有实根”的逆否命题； ④命题“若A ∩B ＝B ，则A ⊆B ”的逆命题．其中是真命题的是__________(写出所有正确命题的序号)．5．双曲线19422-=-y x 的渐近线方程是____________． 6． 已知M (-2,0),N (2,0),|PM |-|PN |=4，则动点P 的轨迹是____________． 7．如果方程x 2+ky 2=2表示焦点在y 轴上的椭圆,那么实数k 的取值范围是____________． 8．已知向量)5,3,2(-=与向量),,4(y x -=平行,则x ,y 的值分别是____________．9．已知ABCD 是平行四边形,且A (4,1,3),B (2,-5,1),C (3,7,-5),则顶点D 的坐标为____________． 10．已知)3,1,3(A ，(1,0,5)B ，则线段AB 的长度为________．11．已知双曲线22221y x a b-=（00a b >>, ）的两个焦点为()10F 、)20F ，点P 是第一象限内双曲线上的点，且121tan 2PF F ∠=，21tan 2PF F ∠=-，则双曲线的离心率为_________．12．已知向量(,12,1),(4,5,1),(,10,1)OA k OB OC k ===-，且A 、B 、C 三点共线，则k = ．13．如图，在正方体1111ABCD A B C D -中，1AB =，1112A P A C = ．则直线PB 与PD 所成角的正弦值为_______．14．在平面直角坐标系xOy中，直角三角形ABC的三个顶点都在椭圆2221 (1)x y aa+=>上，其中0 1A（，）为直角顶点．若该三角形的面积的最大值为27，则实数a的值为_______．三、解答题15．如果正△ABC中，D∈AB，E∈AC，向量12DE BC=，求以B，C为焦点且过点D，E的双曲线的离心率．16．如图，在四棱锥P—ABCD中，底面ABCD为矩形，侧棱PA⊥底面ABCD，AB=3，BC=1，PA=2，E为PD的中点．（Ⅰ）求直线AC与PB所成角的余弦值；（Ⅱ）求二面角A-PD-C的余弦值．PA B CD E ．17．已知直线与抛物线y 2 =2px （p ＞0）交于A 、B 两点，O 为坐标原点，且OA ⊥OB ，OD ⊥AB 交AB 于点D ，点D 的坐标为（2，1），求p 的值．18．如图，已知三棱柱111C B A ABC -的侧棱与底面垂直，AB AC AB AA ，11===⊥AC ，M 是1CC 的中点，N 是BC 的中点，点P 在直线11B A 上，且满足111B A A λ=. （Ⅰ）当λ取何值时，直线PN 与平面ABC 所成的角θ最大？（Ⅱ）若平面PMN 与平面ABC 所成的二面角为45，试确定点P 的位置.1A1BPNM ABC1C19．如图所示，F 1、F 2分别为椭圆C ：)0(12222>>=+b a by a x 的左、右两个焦点，A 、B 为两个顶点，已知椭圆C 上的点)23,1(到F 1、F 2两点的距离之和为4．（Ⅰ）求椭圆C 的方程和焦点坐标；（Ⅱ）过椭圆C 的焦点F 2作AB 的平行线交椭圆于P 、Q 两点，求△F 1PQ 的面积．20． 已知中心在原点的双曲线C 的右焦点为(2,0)，右顶点为)0,3(． (1) 求双曲线C 的方程；(2) 若直线l ：2+=kx y 与双曲线C 恒有两个不同的交点A 和B ，且2>⋅(其中O为原点)，求k 的取值范围．高二数学理科暑假作业（1）参考答案一、填空题 1． [1,2) 2．“若△ABC 有两个内角相等,则它是等腰三角形” 3．充分不必要 4．②③5． x y 23±= 6．一条射线 7． (0,1) 8． 6和-10 9． (5,13,-3) 10． 3 1112．23- 13．14． 3二、解答题15． 解116．解法1：（Ⅰ）建立如图所示的空间直角坐标系，则A 、B 、C 、D 、P 、E 的坐标为A （0，0，0）、B （3，0，0）、C （3，1，0）、D （0，1，0）、 P （0，0，2）、E （0，21，1）， 从而).2,0,3(),0,1,3(-==PB AC 设PB AC 与的夹角为θ，则,1473723||||cos ==⋅=PB AC θ∴AC 与PB 所成角的余弦值为1473． 17．解：1,,2,:12(2)252OD AB AB K OD AB K l y x y x =⊥∴=-∴-=--=-+ 即 211222212121212121212122550,(,),(,)...............42,5,2055,0,0.. (922)5()50,5500 (4)y x y y px p A x y B x y y pxy y p y y p p p y y OA OB x x y y y y y y y y p p p =-+⎧+-=⎨=⎩∴+=-=-=+--⊥∴+=∴∙+=-++=∴-++==> 消去得设分分即解得代入........115/4.......................................................12p ∴=分分18．解：（1）以AB,AC,1AA 分别为,,x y z 轴，建立空间直角坐标系xyz A -，则)1,21,21(--=λ，平面ABC 的一个法向量为(0,0,1)n =则45211,cos sin 2+⎪⎭⎫ ⎝⎛-==><=λθ （*）于是问题转化为二次函数求最值，而[0,],2πθ∈当θ最大时，θsin 最大，所以当21=λ时， 552)(sin max =θ.（3）已知给出了平面PMN 与平面ABC 所成的二面角为45︒，即可得到平面ABC 的一个法向量为1(0,0,1)n AA == ，设平面PMN 的一个法向量为(,,)m x y z = ，1(,1,)2MP λ=- .由⎪⎩⎪⎨⎧=∙=∙00得11()022102x y z x y z λλ⎧--+=⎪⎪⎨⎪-+=⎪⎩ ，解得2132(1)3y x z xλλ+⎧=⎪⎪⎨-⎪=⎪⎩.令3,(3,21,2(1))x m m n λλ==+-得这样和就表示出来了，于是由22)1(4)12(9)1(2,cos 22=-+++-==><λλλ， 解得111,2P B A λ=-故点在的延长线上，且112A P =.19． 解：（Ⅰ）由题设知：2a = 4，即a = 2；将点)23,1(代入椭圆方程得 1)(2122232=+b，解得b 2 = 3； ∴c 2 = a 2－b 2 = 4－3 = 1，故椭圆方程为13422=+y x ，焦点F 1、F 2的坐标分别为（-1，0）和（1，0），（Ⅱ）由（Ⅰ）知)3,0(),0,2(B A -， 23==∴AB PQ k k ，∴PQ 所在直线方程为)1(23-=x y ，由⎪⎪⎩⎪⎪⎨⎧=+-=134)1(2322y x x y 得 093482=-+y y ， 设P (x 1，y 1)，Q (x 2，y 2)，则89,232121-=⋅-=+y y y y ， 221894434)(2122121=⨯+=-+=-∴y y y y y y ，.2212212212121211=⨯⨯=-⋅=∴∆y y F F S PQ F 20．解：（Ⅰ）设双曲线方程为22221x y a b-= ).0,0(>>b a由已知得.1,2,2,32222==+==b b a c a 得再由故双曲线C 的方程为.1322=-y x （Ⅱ）将得代入13222=-+=y x kx y .0926)31(22=---kx x k由直线l与双曲线交于不同的两点得2222130,)36(13)36(1)0.k k k ⎧-≠⎪⎨∆=+-=->⎪⎩即.13122<≠k k 且 ① 设),(),,(B B A A y x B y x A ，则229,,22,131A B A BA B A Bx x x x OA OB x x y y k -+==⋅>+>-- 由得 而2((1)()2A B AB A B A B A B A B x x y y x x kx kx k x x x x +=+=+++22222937(1)2.131331k k k k k -+=+++=--- 于是222237392,0,3131k k k k+-+>>--即解此不等式得.3312<<k ② 由①、②得 .1312<<k 故k 的取值范围为(1,(33--⋃。
2021年高二下学期高考假期作业数学（一）试题含答案1. 已知集合A ＝{x ||x －1|<2}，B ＝⎩⎪⎨⎪⎧⎭⎪⎬⎪⎫x ⎪⎪⎪x －b x ＋2<0，若A ∩B ≠∅，则实数b 的取值范围是________．2. 设M ＝{a |a ＝(2，0)＋m (0，1)，m ∈R }和N ＝{b |b ＝(1，1)＋n (1，－1)，n ∈R }都是元素为向量的集合，则M ∩N ＝________．3. 设集合A ＝(x ，y )⎪⎪⎪m 2≤(x －2)2＋y 2≤m 2，x ，y ∈R ，B ＝{(x ，y )|2m ≤x ＋y ≤2m ＋1，x ，y ∈R }，若A ∩B ≠∅，则实数m 的取值范围为_____．4. 给出下列命题：p ：函数f (x )＝sin 4x －cos 4x 的最小正周期是π；q ：∃x ∈R ，使得log 2(x ＋1)<0；r ：已知向量a ＝(λ，1)，b ＝(－1，λ2)，c ＝(－1,1)，则(a ＋b )∥c 的充要条件是λ＝－1.其中所有的真命题是________．5. 使得关于x 的方程ax 2＋2x ＋1＝0至少有一个负实根的充要条件的a 的取值范围是________．6.若命题“∃x ∈R ，有x 2－mx －m <0”是假命题，则实数m 的取值范围是________．7. 设f (2x －1)＝2x －1，则f (x )的定义域是________．8. 设f (x )＝⎩⎪⎨⎪⎧ |x －1|－2，|x |≤1，11＋x 2，|x |>1，则f ⎝ ⎛⎭⎪⎫f ⎝ ⎛⎭⎪⎫12等于________． 9. 设函数f (x )＝－x 2－2x ＋15，集合A ＝{x |y ＝f (x )}，B ＝{y |y ＝f (x )}，则A ∩B ＝________.10．若一系列函数的解析式相同，值域相同但定义域不同，则称这些函数为“孪生函数”，那么函数解析式为y ＝2x 2＋1，值域为{3,19}的“孪生函数”共有________个．11. f (x )的定义域为R ，f (－1)＝2，对任意x ∈R ，f ′ (x )＞2，则f (x )＞2x ＋4的解集为________．12. 已知f (x )是定义在(－1,1)上的奇函数，且f (x )在(－1,1)上是减函数，则不等式f (1－x )＋f (1－x 2)＜0的解集为________．13. 设f (x )是定义在R 上的增函数，且对于任意的x 都有f (1－x )＋f (1＋x )＝0恒成立．如果实数m 、n 满足不等式组⎩⎨⎧m >3，f (m 2－6m ＋23)＋f (n 2－8n )<0，那么m 2＋n 2的取值范围是________．14. ．已知定义在R 上的函数y ＝f (x )满足条件f ⎝ ⎛⎭⎪⎫x ＋32＝－f (x )，且函数y ＝f ⎝ ⎛⎭⎪⎫x －34为奇函数，给出以下四个命题：①函数f (x )是周期函数；②函数f (x )的图象关于点⎝ ⎛⎭⎪⎫－34，0对称；③函数f (x )为R 上的偶函数；④函数f (x )为R 上的单调函数．其中真命题的序号为________(写出所有真命题的序号)．15. (1)已知f (x )是R 上的奇函数，且当x >0时，f (x )＝x 2－x －1，求f (x )的解析式；(2)设a >0，f (x )＝e x a ＋a e x 是R 上的偶函数，求实数a 的值；(3)已知奇函数f (x )的定义域为，且在区间内递减，求满足f (1－m )＋f (1－m 2)<0的实数m 的取值范围．16. 设二次函数f (x )＝ax 2＋bx ＋c (a ≠0)在区间上的最大值、最小值分别是M ，m ，集合A ＝{x |f (x )＝x }．(1)若A ＝{1,2}，且f (0)＝2，求M 和m 的值；(2)若A ＝{1}，且a ≥1，记g (a )＝M ＋m ，求g (a )的最小值．17. 设函数f(x)＝ka x－a－x(a＞0且a≠1)是奇函数．(1)求k的值；(2)若f(1)＞0，解关于x的不等式f(x2＋2x)＋f(x－4)＞0；(3)若f(1)＝32，且g(x)＝a2x＋a－2x－2mf(x)在18. 已知函数f(x)＝|x－a|－a2ln x，a∈R.(1)求函数f(x)的单调区间；(2)若函数f(x)有两个零点x1，x2(x1<x2)，求证：1<x1<a<x2<a2.19. 为了在夏季降温和冬季供暖时减少能源损耗，房屋的房顶和外墙需要建造隔热层．某幢建筑物要建造可使用20年的隔热层，每厘米厚的隔热层建造成本为6万元．该建筑物每年的能源消耗费用C(单位：万元)与隔热层厚度x(单位：cm)满足关系：C(x)＝k3x＋5(0≤x≤10)，若不建隔热层，每年能源消耗费用为8万元．设f(x)为隔热层建造费用与20年的能源消耗费用之和．(1)求k的值及f(x)的表达式；(2)隔热层修建多厚时，总费用f(x)达到最小，并求最小值．20. 制订投资计划时，不仅要考虑可能获得的盈利，而且要考虑可能出现的亏损．某投资人打算投资甲、乙两个项目，根据预测，甲、乙项目可能的最大盈利率分别为100%和50%，可能的最大亏损率分别为30%和10%.若投资人计划投资金额不超过10万元，要求确保可能的资金亏损不超过1.8万元，问投资人对甲、乙两个项目各投资多少万元，才能使可能的盈利最大？作业一答案1.(－1，＋∞)2. {(2，0)}3. ⎣⎢⎡⎦⎥⎤12，2＋2 4. p 、q 5. (－∞，1] 6. －4≤m ≤0 7. (－1，＋∞) 8. 413 9. 10. 911. (－1，＋∞) 12. (0,1) 13. (13,49) 14. ①③15. 解 (1)∵f (x )是定义在R 上的奇函数，∴f (0)＝0，当x <0时，－x >0，由已知f (－x )＝(－x )2－(－x )－1＝x 2＋x －1＝－f (x )．∴f (x )＝－x 2－x ＋1.∴f (x )＝⎩⎪⎨⎪⎧ x 2－x －1，x >0，0，x ＝0，－x 2－x ＋1，x <0.(2)∵f (x )是R 上的偶函数，∴f (－x )＝f (x )在R 上恒成立．即e －x a ＋a e －x ＝e x a ＋a e x ， (a 2－1)(e 2x －1)＝0，对任意的x 恒成立，∴⎩⎪⎨⎪⎧a 2－1＝0，a >0，解得a ＝1. (3)∵f (x )的定义域为，∴有⎩⎪⎨⎪⎧－2≤1－m ≤2，－2≤1－m 2≤2，解得－1≤m ≤ 3.① 又f (x )为奇函数，且在上递减，∴在上递减，∴f (1－m )<－f (1－m 2)＝f (m 2－1)⇒1－m >m 2－1，即－2<m <1.②综合①②，可知－1≤m <1.16. 解 (1)由f (0)＝2可知c ＝2.又A ＝{1,2}，故1,2是方程ax 2＋(b －1)x ＋2＝0的两实根．所以⎩⎪⎨⎪⎧1＋2＝1－b a ，2＝2a .解得a ＝1，b ＝－2. 所以f (x )＝x 2－2x ＋2＝(x －1) 2＋1，x ∈． 当x ＝1时，f (x )min ＝f (1)＝1，即m ＝1.当x ＝－2时，f (x )max ＝f (－2)＝10，即M ＝10.(2)由题意知，方程ax 2＋(b －1)x ＋c ＝0有两相等实根x ＝1.所以⎩⎪⎨⎪⎧ 1＋1＝1－b a ，1＝c a ，即⎩⎨⎧b ＝1－2a ，c ＝a . 所以f (x )＝ax 2＋(1－2a )x ＋a ，x ∈，其对称轴方程为x ＝2a －12a ＝1－12a .又a ≥1，故1－12a ∈⎣⎢⎡⎭⎪⎫12，1. 所以M ＝f (－2)＝9a －2.m ＝f ⎝ ⎛⎭⎪⎫2a －12a ＝1－14a . g (a )＝M ＋m ＝9a －14a －1.又g (a )在区间(2)因为f (1)＞0，所以a －1a ＞0，∴a ＞1，∴f (x )＝a x －a －x 是R 上的单调增函数．于是由f (x 2＋2x )＞－f (x －4)＝f (4－x )，得x 2＋2x ＞4－x ，即x 2＋3x －4＞0，解得x ＜－4或x ＞1.(3)因为f (1)＝32，所以a －1a ＝32，解得a ＝2(a ＞0)，所以g (x )＝22x ＋2－2x －2m (2x－2－x )＝(2x －2－x )2－2m (2x －2－x )＋2.设t ＝f (x )＝2x －2－x ，则由x ≥1，得t ≥f (1)＝32，g (x )＝t 2－2mt ＋2＝(t －m )2＋2－m 2.若m≥32，则当t＝m时，y min＝2－m2＝－2，解得m＝2.若m＜32，则当t＝32时，y min＝174－3m＝－2，解得m＝2512(舍去)．综上得m＝2.18. (1)解由题意，函数的定义域为(0，＋∞)，当a≤0时，f(x)＝|x－a|－a2ln x＝x－a－a2ln x，f′(x)＝1－a2x>0，函数f(x)的单调递增区间为(0，＋∞)．当a>0时，f(x)＝|x－a|－a2ln x＝⎩⎪⎨⎪⎧x－a－a2ln x，x≥a，a－x－a2ln x，0<x<a，若x≥a，f′(x)＝1－a2x＝2x－a2x>0，此时函数f(x)单调递增，若0<x<a，f′(x)＝－1－a2x<0，此时函数f(x)单调递减，综上，当a≤0时，函数f(x)的单调递增区间为(0，＋∞)；当a>0时，函数f(x)的单调递减区间为(0，a)；单调递增区间为(a，＋∞)．(2)证明由(1)知，当a≤0时，函数f(x)单调递增，至多只有一个零点，不合题意；则必有a>0，此时函数f(x)的单调递减区间为(0，a)；单调递增区间为(a，＋∞)，由题意，必须f(a)＝－a2ln a<0，解得a>1.由f(1)＝a－1－a2ln 1＝a－1>0，f(a)<0，得x1∈(1，a)．而f(a2)＝a2－a－a ln a＝a(a－1－ln a)，下面证明：a>1时，a－1－ln a>0.设g(x)＝x－1－ln x，x>1，则g′(x)＝1－1x＝x－1x>0，∴g(x)在x>1时递增，则g(x)>g(1)＝0，∴f(a 2)＝a 2－a －a ln a ＝a (a －1－ln a )>0，又f (a )<0，∴x 2∈(a ，a 2)，综上，1<x 1<a <x 2<a 2.19. 解 (1)设隔热层厚度为x cm ，由题设，每年能源消耗费用为C (x )＝k 3x ＋5，再由C (0)＝8，得k ＝40，因此C (x )＝403x ＋5. 而建造费用为C 1(x )＝6x .最后得隔热层建造费用与20年的能源消耗费用之和为f (x )＝20C (x )＋C 1(x )＝20×403x ＋5＋6x ＝8003x ＋5＋6x (0≤x ≤10)． (2)f (x )＝2⎣⎢⎡⎦⎥⎤4003x ＋5＋(3x ＋5)－10≥2×2400－10＝70(当且仅当4003x ＋5＝3x ＋5，即x ＝5时，“＝”成立)，所以当x ＝5时，f (x )min ＝f (5)＝70.故隔热层修建5 cm 厚时，总费用达到最小值70万元.20. 解 设投资人分别用x 万元、y 万元投资甲、乙两个项目，由题意知⎩⎪⎨⎪⎧ x ＋y ≤10，0.3x ＋0.1y ≤1.8，x ≥0，y ≥0，目标函数z ＝x ＋0.5y .上述不等式组表示的平面区域如图所示，阴影部分(含边界)即为可行域．将z ＝x ＋0.5y 变形为y ＝－2x ＋2z ，这是斜率为－2、随z 变化的一组平行线，当直线y ＝－2x ＋2z 经过可行域内的点M 时，直线y ＝－2x ＋2z 在y 轴上的截距2z 最大，z 也最大．这里M 点是直线x ＋y ＝10和0.3x ＋0. 1y ＝1.8的交点．解方程组⎩⎪⎨⎪⎧x ＋y ＝10，0.3x ＋0.1y ＝1.8，得x ＝4，y ＝6，此时z ＝4＋0.5×6＝7(万元)．∵7＞0，∴当x ＝4，y ＝6时，z 取得最大值，所以投资人用4万元投资甲项目、6万元投资乙项目，才能在确保亏损不超过1.8万元的前提下，使可能的盈利最大． 20085 4E75 乵8WM 38753 9761 靡27591 6BC7 毇136351 8DFF 跿:25274 62BA 抺r^20893 519D 冝n。
武汉市高二物理寒假作业01一、单选题（本大题共6小题，共24.0分）1.下列说法正确的是（）A. 电场中电势为零的点，电场强度一定为零B. 电场中任一点的电场强度总是指向该点电势降落的方向C. 电源的电动势就等于电源两极间的电压D. 电流、电势差磁通量均有正负之分，但它们都是标量2.已知一无限长的直导线中通有电流时，该直导线周围某点磁感应强度的大小与该点到直线的距离成反比，与电流大小成正比。
如图所示，两条平行长直导线中通以大小相等、方向相反的电流，其中A导线电流垂直纸面向里，B导线电流垂直纸面向外，C为AB的中点。
则下列说法正确的是（）A. 在AB两点之间的连线上，C点磁感应强度最小B. 在图中连线上，A点左侧不同位置磁感应强度方向不同C. C点磁感应强度方向在纸面内垂直AB向上D. 两条平行长直导线在安培力的作用下相互吸引3.如图所示，虚线为一带正电的粒子在匀强电场中的一段运动轨迹，水平实线为电场的等势线，不计粒子重力，下列说法正确的是（）A. 粒子一定由A向B运动B. 匀强电场方向竖直向上C. 粒子在B点的电势能比在A点的小D. 粒子运动过程中机械能守恒4.如图所示电路中，电源内阻为r，R1、R2为定值电阻，且r＜R1，各电表均为理想电表。
开关S闭合后，在滑动变阻器R0的滑片向下滑动的过程中，下列说法正确的是（）A. 电流表与两只电压表的示数都减小B. 电压表与电流表的示数减小，电压表的示数增大C. 电压表比电压表的示数变化量的绝对值大D. 电源的输出功率减小5.如图所示正方形区域内存在着垂直纸面向里的匀强磁场，粒子a、b以相同的初速度从正方形某一边的中点垂直于边界进人磁场区域，粒子离开磁场的位置恰好在图中两个顶点，已知sin53°=0.8，cos53°=0.6．则下列说法正确的是（）A. a带负电，b带正电B. a、b的比荷之比为5：1C. a．b在磁场中运动的周期之比为5：1D. a．b在磁场中运动的时间之比为180：536.如图所示。
