托福TPO49综合写作阅读原文+听力原文+满分范文

TPO49阅读-1Background for the Industrial Revolution原文 (1)译文 (2)题目 (3)答案 (8)背景知识 (8)原文Background for the Industrial Revolution①The Industrial Revolution had several roots, one of which was a commercial revolution that, beginning as far back as the sixteenth century, accompanied Europe’s expansion overseas. Both exports and imports showed spectacular growth, particularly in England and France. An increasingly larger portion of the stepped-up commercial activity was the result of trade with overseas colonies. Imports included a variety of new beverages, spices, and ship’s goods around the world and brought money flowing back. Europe’s economic institutions, particularly those in England, were strong, had wealth available for new investment, and seemed almost to be waiting for some technological breakthrough that would expand their profit-making potential even more.②The breakthrough came in Great Britain, where several economic advantages created a climate especially favorable to the encouragement of new technology. One was its geographic location at the crossroads of international trade. Internally, Britain was endowed with easily navigable natural waterway, which helped its trade and communication with the world. Beginning in the 1770’s, it enjoyed a boom in canal building, which helped make its domestic market more accessible. Because water transportation was the cheapest means of carrying goods to market, canals reduced prices and thus increased consumer demand. Great Britain also had rich deposits of coal that fed the factories springing up in industrial and consumer goods.③Another advantage was Britain’s large population of rural, agricultural wage earners, as well as cottage workers, who had the potential of being more mobile than peasants of some other countries. Eventually they found their way to the cities or mining communities and provided the human power upon which the Industrial Revolution was built. The British people were also consumers; the absence of internal tariffs, such as those that existed in France or Italy or between the German states, made Britain the largest free-trade area in Europe. Britain’s relatively stable government also helped create an atmosphere conducive to industrial progress.④Great Britain’s better-developed banking and credit system also helped speed the industrial progress, as did the fact that it was the home of an impressive array of entrepreneurs and inventors. Among them were a large number of nonconformists whose religious principles encouraged thrift and industry rather than luxurious living and who tended to pour their profits back into their business, thus providing the basis for continued expansion.⑤A precursor to the Industrial Revolution was a revolution in agricultural techniques. Ideas about agricultural reform developed first in Holland, where as early as the mid-seventeenth century, such modern methods as crop rotation, heavy fertilization, and diversification were all in use. Dutch peasant farmers were known throughout Europe for their agricultural innovations, but as British markets and opportunities grew, the English quickly learned from them. As early as the seventeenth century the Dutch were helping them drain marshes and fens where, with the help of advanced techniques, they grew new crops. By the mid-eighteenth century new agricultural methods as well as selective breeding of livestock had caught on throughout the country.⑥Much of the increased production was consumed by Great Britain’s burgeoning population. At the same time, people were moving to the city, partly because of the enclosure movement; that is, the fencing of common fields and pastures in order to provide more compact, efficient privately held agricultural parcels that would produce more goods and greater profits. In the sixteenth century enclosures were usually used for creating sheep pastures, but by the eighteenth century new farming techniques made it advantageous for large landowners to seek enclosures in order to improve agricultural production. Between 1714 and 1820 over 6 million acres of English land were enclosed. As a result, many small, independent farmers were forced to sell out simply because they could not compete. Non-landholding peasants and cottage workers, who worked for wages and grazed cows or pigs on the village common, were also hurt when the common was no longer available. It was such people who began to flock to the cities seeking employment and who found work in the factories that would transform the nation and, the world.译文工业革命的背景①工业革命有几个根源，其中之一是随着欧洲的海外扩张，早在16世纪就开始的商业革命。

为了帮助大家高效备考托福，为大家带来托福TPO50综合写作阅读原文+听力原文+满分范文，希望对大家备考有所帮助。

托福TPO50综合写作阅读原文文本： Scientists are considering the possibility of sending humans to Mars in the coming decades. Although there have been successful manned missions to the Moon in the 1960s and 1970s, Mars is 150 times further away from Earth than the Moon is. Thus the project of sending humans to Mars would require solving an array of problems the Moon missions did not have to face. One problem is that a round-trip to Mars and back is likely to take at least two years. The trip to the Moon lasted only a few days, and it was easy to bring enough supplies of food, water, and oxygen; but the cargo capacity of space vehicles is too limited to put on board the food, water, and oxygen required by a crew for a period of two years. Without those essentials, though, a Mars mission is impossible. A second problem is that astronauts on the Mars mission would be in the zero-gravity environment of space for many months at a time. Spending a long time in the zero-gravity environment has negative effects on the human body, such as decreased muscle mass and lower bone density. Over the course of a two-year mission, the effects would be so severe, they would make it impossible for humans to make the trip without experiencing grave medical problems. Finally, astronauts on a mission to Mars would be exposed to dangerous levels of space radiation, much of which comes in the form of charged particles emitted by the Sun. Earth's magnetic field, which normally protects us from dangerous solar radiation, would not be able to protect a spaceship traveling in interplanetary space. Constructing a shield that would protect the whole spaceship from space radiation is at present impossible because it would add too much weight to the ship. 托福TPO50综合写作听力原文文本： A trip to mars would definitely be challenging but scientists have proposed solutions to the problems the reading selection discusses. First of all, food, water and oxygen. Well astronauts can use hydroponics. Hydroponics is a technique for growing plants with their roots in water rather than in soil. It requires relatively little space. Using hydroponics, the astronauts should be able to cultivate food crops in the spacecraft. In addition, the hydroponic will grow plants with recycle waste water and release it as clean water vapor, which can be collected as drinking water. And of course, all plants absorb carbon dioxide and release oxygen. So thanks to hydroponics the astronauts will also have fresh air to breathe. Second, the effects of zero gravity. Over the last few decades, we have launched several space stations orbiting the earth. And a number of astronauts have spent many months on them in a zero gravity environment. These astronauts have learned to useseveral techniques to safely manage the effects of zero gravity. For example, regular exercise prevents the decrease in muscle mass. Likewise, taking vitamins and minerals like calcium slows down the decrease in astronauts’ bone density. Third, solar radiation. Astronauts traveling to Mars will be exposed to some solar radiation but this radiation will not be at dangerous levels all the time. The sun only releases dangerous amounts of radiation occasionally, during periods when it is particularly active. In order to avoid this threat, the spacecraft could be equipped with special instruments that monitor solar radiation and with a small shelter that shield against radiation but doesn’t add much weight to the ship. Most of the time, the astronauts will go about their normal business in unshielded areas of the spacecraft. But when their instruments detect increased radiation, they could stay in the small shielded area until the danger has passed. 托福TPO50综合写作满分范文： Both the reading and listening are arguing over a question whether it is possible to send human being to Mars. The reading lists out three problems to a successful carrying out. However, the listening offers three solutions to these questions. First, the reading raises the question that it takes too long to send people to Mars, approximately two years and no spacecraft could take that many loads of food, water and life essentials. Instead, the listening says this is not a real problem since the astronauts could use hydroponics to grow crop plants in water and food will not be an obstacle. Also, they could grow plants with recycle waste water and reuse it as clean water vapor, which could be drunk. Plus, since all plants do photosynthesis, the astronauts could breathe fresh air released by them. Second, the reading asserts that living in a zero-gravity environment would exert a negative effect on one’s health. Nevertheless, the professor says that the astronauts have learned to use several techniques to make up for the health issue. They will do regular exercise to prevent muscle mass from decreasing and take vitamins and minerals to slow down problem with their bone density. In another word, they’ve figured out how to cope with the potential health problem. Third, the reading claims that radiation emitted by the sun would be dangerous to astronauts. This time professor subtly rejects by pointing out that a third solution has come out. The spaceship would be equipped with a special instrument to monitor the radiation. What’s more, the device could also shield against the radiation. When astronauts meet the period of a large amount of radiation, they could hide behind the shielded areas and come out when the danger has passed. 以上是给大家整理的托福TPO50综合写作阅读原文+听力原文+满分范文，希望对你有所帮助!。

托福阅读真题第49篇TheAngiospermRevolution在所有种类的现代陆地植物中，有一组占主导地位：被子植物或开花植物。

它们拥有超过250,000 种生物，是大多数栖息地中的大多数植物——海洋环境除外，海洋环境仍然是更原始藻类的栖息地。

但是被子植物是植物进化中相对较新的发展。

它们出现于中生代中期（约 2 亿年前至 1.45 亿年前），但距今约 1 亿年ago they had pushed the conifers (plants having cone-shaped reproductive structures rather than flowers for reproduction) into the background. Even earlier types of plants such as ferns are now restricted to certain wet habitats, and many of the dominant gymnosperms (plants with exposed seeds, such as conifers) of the early Mesozoic have now been largely replaced by angiosperms; the formerly dominant gymnosperms that did not become completely extinct now survive in comparatively few places.Why were the angiosperms so successful? A major advantage they have over more primitive plants is their efficient mode of reproduction- -the flower and all of its complex reproductive mechanisms that ensure success. Instead of the inefficient wind-pollinated gymnosperm seed, which wastes a huge amount of pollen and is dependent on random breezes, angiosperms have evolved flowers specifically as devices to attract pollinators- -mainly insects (especially moths, butterflies, and bees) but also birds, bats, and other flying creatures. The pollinators ensure that the pollen is carried directly from one flower of the same species to another, which is more efficient than relying on the wind. This process of delivery is called cross-pollination. The reproductive cycle is highly modified: the ovules (egg-producing organs) are fully enclosed within protectivecovers called carpels, which form the core of the flower. The carpel protects the ovule from drying out, from fungal infection, and from predation by plant-eating insects. Pollen-producing organs called stamens are surrounded by petals (which serve to attract the pollinator and guide it to the ovules in many cases) and an outer covering of sepals for protection. Typically, a pollinator gets pollen stuck onto it as it climbs into a flower, seeking the nectar that is generated to lure it. The ovule is usually pollinated by the sperm carried from a different flower, thus minimizing self-fertilization (but angiosperms can also self-fertilize if cross-pollination is not possible).Once the pollen has been delivered, a pollen tube transports the sperm to the ovules. Here angiosperms have another advantage: double fertilization. The pollen carry two sperm nuclei, one of which fuses with the egg nucleus to form the embryo, the other of which fuses with two other nuclei to form a food supply for the embryo. This means that angiosperms don't need to invest a lot of energy creating food stores for each seed until it is fertilized (unlike gymnosperms, which create food even for infertile seeds).The entire process of fertilization and producing an embryo takes place in only a few weeks or days, so angiosperms can sprout, flower, reproduce, and die in a single season if necessary. By contrast, most gymnosperms are slow to grow and reproduce (usually taking at least eighteen months between reproductive cycles) and cannot accomplish the entire process in a single season. For gymnosperms such as evergreen conifers to live in highly seasonal, cold-winter climates, they must be able to survive the cold and shut down much of their physiological systems during winter. Many angiosperms, on the other hand, areannuals- sprouting in the spring, flowering, and producing seeds that can survive until the next winter while the rest of the plant dies. This rapid reproduction enables them to quickly exploit habitats that other plants cannot.Finally, angiosperms are known not only for their rapid growth rates but for their ability to grow back quickly after they have been munched by animals. Think of how quickly the grass grows back after you mow it (or an animal grazes it). By contrast, ferns cannot grow back so quickly after they have been heavily eaten, and often die if the damage is too great (such as when an animal eats the growing tip of the plant)- whereas many angiosperms can be eaten right down to their roots but grow back again.1.Of all the kinds of modern land plants one group dominates: the angiosperms, or flowering plants. With over 250,000 living species, they are the majority of plants of most habitats- except marine environments, which are still habitats for the more primitive algae. But angiosperms were a comparatively recent development in plant evolution. They arose in the mid-Mesozoic (approximately 200 million years ago to 145 million years ago), but by about 100 million years ago they had pushed the conifers (plants having cone-shaped reproductive structures rather than flowers for reproduction) into the background. Even earlier types of plants such as ferns are now restricted to certain wet habitats, and many of the dominant gymnosperms (plants with exposed seeds, such as conifers) of the early Mesozoic have now been largely replaced by angiosperms; the formerly dominant gymnosperms that did not become completely extinct now survive in comparatively few places.。

为了帮助大家高效备考托福，为大家带来托福TPO49独立写作题目文本+满分范文，希望对大家备考有所帮助。

托福TPO49独立写作题目原文： Do you agree or disagree with the following statement? The ability to maintain friendships with a small number of people over a long period of time is more important for happiness than the ability to make many new friends easily. Use specific reasons and examples to support your answer. 托福TPO49独立写作满分范文： Friendship and kinship contribute a lot to one’s happiness. Then, the question goes, “does the ability to main long-term friendships with a small number of people matters more than the ability to make many new friends easily?” My answer is “yes”. First of all, old friends usually show stronger loyalty than those newly-acquainted fellows. That means, no matter what happens, these friends would always stand by your side and provide you with supports unconditionally. However, this merit are usually missing in short-term friendship. Last year when I was in hospital, 2 of my old friends took turns to take care of me, accompanying me to endure the very hard time. However, few of my “wide-range” new friends even came to visit me. It is clearly that long-term friendship is much more reliable and the ability to main such kind of relationship is more critical. In addition, old friends tend to show more understanding of you, being familiar with your hobbies, interests and some other peculiarities. So, it is usually more comfortable for me to be with my old friends. For instance, I am lactose intolerant and every time when I have dinner with my old friends, they would skip anything that contains milk or cheese, ordering food based on my favor. Contrary to my old friends’ consideration, those newly-acquainted fellows are inclined to show surprise about my intolerance and still pick the food of lactose they prefer. So, to me, old friends are much more considerate and contribute more to my happiness. Admittedly, the ability to make new friends easily are quite important for a person to get new ideas, broadening their views from different groups of people. However, compared with the ability to maintain long-term friendship, it still plays a less significant role for one’s happiness. To sum up, one’s happiness is consist of various parts, including self-achievement, security and etc. And I believe long-term friendship is of higherimportance than other parts. As a result, the ability to maintain long-term friendship with a small group of people is much more important. 以上是给大家整理的托福TPO49独立写作题目文本+满分范文，希望对你有所帮助!。

TPO49阅读-2 Movable Type原文 (1)译文 (2)题目 (4)答案 (8)背景知识 (8)原文Movable Type①Nothing divided the medieval world in Europe more decisively from the Early Modern period than printing with movable type. It was a German invention and the culmination of a complex process. The world of antiquity had recorded its writings mainly on papyrus. Between 200 B.C and A.D 300, this was supplemented by vellum, calf skin treated and then smoothed by pumice stone. To this in late Roman times was added parchment, similarly made from the smoothed skin of sheep or goats. In the early Middle Ages, Europe imported an industrial process from China, which turned almost any kind of fibrous material into pulp that was then spread in sheets. This was known as cloth parchment. By about 1150, the Spanish had developed the first mill for making cheap paper (a word contracted from "papyrus", which became the standard term). One of the most important phenomena of the later Middle Ages was the growing availability of cheap paper. Even in England, where technology lagged far behind, a sheet of paper, or eight octavo pages, cost only a penny by the fifteenth century.②In the years 1446-1448, two German goldsmiths, Johannes Gutenberg and Johann Fust, made use of cheap paper to introduce a critical improvement in the way written pages were reproduced. Printing from wooden blocks was the old method; what the Germans did was to invent movable type for the letterpress. It had three merits: it could be used repeatedly until worn out; it was cast in metal from a mold and so could be renewed without difficulty; and it made lettering uniform. In 1450, Gutenberg began work on his Bible, the first printed book, known as the Gutenberg. It was completed in 1455 and is a marvel. As Gutenberg, apart from getting the key idea, had to solve a lot of practical problems, including imposing paper and ink into the process and the actual printing itself, for which he adapted the screw press used by winemakers, it is amazing that his first product does not look at all rudimentary. Those who handle it are struck by its clarity and quality.③Printing was one of those technical revolutions that developed its own momentum at extraordinary speed. Europe in the fifteenth century was a place where intermediate technology - that is, workshops with skilled craftspeople - waswell established and spreading fast, especially in Germany and Italy. Such workshops were able to take on printing easily, and it thus became Europe's first true industry. The process was aided by two factors: the new demand for cheap classical texts and the translation of the Latin Bible into "modern" languages. Works of reference were also in demand. Presses sprang up in several German cities, and by 1470, Nuremberg, Germany had established itself as the center of the international publishing trade, printing books from 24 presses and distributing them at trade fairs all over western and central Europe. The old monastic scriptoria-monastery workshops where monks copied texts by hand-worked closely alongside the new presses, continuing to produce the luxury goods that movable-type printing could not yet supply. Printing, however, was primarily aimed at a cheap mass sale.④Although there was no competition between the technologies, there was rivalry between nations. The Italians made energetic and successful efforts to catch up with Germany. Their most successful scriptorium quickly imported two leading German printers to set up presses in their book-producing shop. German printers had the disadvantage of working with the complex typeface that the Italians sneeringly referred to as "Gothic" and that later became known as black letter. Outside Germany, readers found this typeface disagreeable. The Italians, on the other hand, had a clear typeface known as roman that became the type of the future.⑤Hence, although the Germans made use of the paper revolution to introduce movable type, the Italians went far to regain the initiative by their artistry. By 1500 there were printing firms in 60 German cities, but there were 150 presses in Venice alone. However, since many nations and governments wanted their own presses, the trade quickly became international. The cumulative impact of this industrial spread was spectacular. Before printing, only the very largest libraries, of which there were a dozen in Europe, had as many as 600 books. The total number of books on the entire Continent was well under 100,000. But by 1500, after only 45 years of the printed book, there were 9 million in circulation.译文活字印刷①没有什么比活字印刷更能够将欧洲的中世纪和近代早期区分开来。

Like the saying goes, “Life without friends is just like desert”. The more friends we have, the more support we can get. While many people attach more importance to developing the ability of making new friends within a short period of time, I believed that the ability of maintaining friendship with a small group of people over a long period of time for happiness is more significant.First and foremost, old friends create easy atmosphere for you. This is because they easily know your likes and dislikes. So, there will be probably fewer barriers that can prevent you from exchanging ideas in a easy way..Let’s understand it in this way, when you are with new friends, you have to be careful with “des and dons”, but spending time with old friends, it is a totally different story. They enable us to enjoy the free atmosphere and this kind of happiness may be stay longer in your memories.Second, old friends are mostly loyal to you. Old friends are those who have been through many ups and downs with you, which means that, they know you well and will never leave you when you are down. For example if a person, who calls him/herself your best friend always intends to take advantage of you, he/she may be your new ‘friend’ just for a short period of time, but will ultimately abandon you at the moment when something adverse happens. In contrast , with old friends , nothing like that will happen in the similar situation. Everyone wants tostay with those who truly care about you. An old friend may not as friendly as you expect, and sometimes, he/she may point out your mistakes .but he is truly loyal to you. With the fidelity, your friendship will definitely last for a long time. Maybe you do not feel happy at first, but as the time goes by, you will gradually feel the warmth and happiness, which are untellable and uniquely different from the feelings coming from new friends.Some people may think that “the more friends I have, the more support and happiness I can get. So it is necessary to make as many friends as possible I can in a short time to expand my social sphere “. Such opinions are right in the front half of the sentence and totally wrong in the remaining. Making more friends is good, but the quality of your friendship is essential too. A real friend can give you support and real happiness while others may just give you support when you are in good condition or they make friends with you for some special purpose, and this way your happiness will always be temporary.So as you can see, true happiness only comes from the person that really cares about you, and the happiness that can’t be felt at first but can be gradually be felt as the time goes by is your real happiness。

托福听力tpo49section2对话讲座原文+题目+答案+译文Conversation2 (1)原文 (1)题目 (4)答案 (5)译文 (5)Lecture3 (7)原文 (7)题目 (10)答案 (12)译文 (12)Lecture4 (14)原文 (14)题目 (16)答案 (18)译文 (18)Conversation2原文NARRATOR:Listen to a conversation between a student and a professor.MALE PROFESSOR:Oh hi Melanie,how are you doing?FEMALE STUDENT:I'm good thanks.I just have some questions about this paper,for your class.Do you have a second to talk about it now?MALE PROFESSOR:Oh yes,no problem;I have about20minutes before my next class.Will that be enough time?FEMALE STUDENT:Yeah I think so.Okay so the thing is,you know,okay I'm writing my paper on the history of jazz in New York City.MALE PROFESSOR:Alright,well that's a pretty broad subject.FEMALE STUDENT:Well actually I'm focusing on a specific decade–the50s–and on and I’m only doing it on a few specific artists.MALE PROFESSOR:Oh okay–because I was going to say that seemed a bit,ah,too ambitious for a10page paper.FEMALE STUDENT:Yeah.No,it's not the subject I'm having trouble with–actually the paper is practically writing itself,I mean I’ve got a lot to say and it’s going pretty well.The thing is,I have this idea…that might make it better and I was wondering if there’s any way I could get an extension…I mean I know it’s due next week right?MALE PROFESSOR:That's right,on Monday.But I don't understand,it sounds like you’re doing so well;why do you need more time?FEMALE STUDENT:Yeah well,I could write the paper as it is and turn it in on time and it would be fine…MALE PROFESSOR:But…?FEMALE STUDENT:But I was just talking to one of my friends,whose family has lived in New York forever,and it turns out that her grandfather was actually there in the period of jazz I'm writing about–I mean he was a jazz musician and he actually,like personally knew the artists I'm writing about.MALE PROFESSOR:You're kidding!Well that’s a coincidence.FEMALE STUDENT:Yeah,I know,it's cool,right?So anyway,that's why I waswondering if I could get an extension,because I thought it would be really great if I could like,interview him,for my paper…MALE PROFESSOR:Ah.FEMALE STUDENT:But I don’t think I can meet with him until early next week,so [trailing off]…MALE PROFESSOR:Ah I see,well!It would certainly add a new dimension to your paper,wouldn’t it?Have you talked with this gentleman yet?FEMALE STUDENT:Um,no,but I talked to my friend,just,you know ran the idea past her,and she said he would probably love to do it.But,you know,he's busy until next week.MALE PROFESSOR:Okay well,yeah!I think that in this case we can definitely extend your deadline until,let’s say,Friday next week?FEMALE STUDENT:Okay that would be great.MALE PROFESSOR:But just to be fair,why don't you turn in an outline of your paper on the due date.FEMALE STUDENT:The outline...oh that's no problem.It's basically done except for the parts about the interview...MALE PROFESSOR:Oh yeah...the interview.Could you have the questions ready then too...the ones you’re planning on asking?FEMALE STUDENT:Sure,yeah I can do that,too.MALE PROFESSOR:And then I'll expect the final draft next Friday.FEMALE STUDENT:Okay great!Thanks.MALE PROFESSOR:Sure,I'm looking forward to reading it!题目1.Why does the student go to see the professor?A.To ask if she can interview him for her paperB.To ask permission to extend the length of her paperC.To ask permission to change the topic of her paperD.To ask for more time to finish her paper2.What can be inferred about the student's work on her paper so far?A.She received a lot of help on the paper from professional musicians.B.She has found enough information to complete the paper.C.She did not start working on the paper early enough.D.She is having difficulty finding sources for the paper.3.Why does the student want to interview her friend's grandfather?A.He has written articles about jazz music in New York City.B.He has recordings of the musicians discussed in the woman's paper.C.He owned a historic jazz club in New York City.D.He was a jazz musician during the1950s.4.What does the professor ask the student to do on the original due date of the paper?[Click on two answers.]A.Turn in her first draftB.Hand in an outlineC.Submit interview questionsD.Confirm that she has scheduled an interview5.Why does the student say this:Professor:All right.Well,that's a pretty broad subject.Student:Well,actually I'm focusing on a specific decade,the50s.A.To address the professor's concernB.To explain a change in her approach to her paperC.To restate the professor's pointD.To request approval of her topic答案D B D BC A译文旁白：听一段学生和教授之间的对话。

托福听力tpo49lecture1、2、3、4原文+题目+答案+译文Lecture1 (1)原文 (1)题目 (4)答案 (6)译文 (6)Lecture2 (8)原文 (8)题目 (10)答案 (12)译文 (12)Lecture3 (14)原文 (14)题目 (17)答案 (19)译文 (19)Lecture4 (21)原文 (21)题目 (23)答案 (25)译文 (25)Lecture1原文NARRATOR:Listen to part of a lecture in a geology class.MALE PROFESSOR:Alaska is fascinating to geologists because of its incrediblelandscapes.Uh,permafrost has a lot to do with this.That is,the areas where the ground—the soil—is always frozen,except for the very top layer—what we call the active layer of permafrost—which melts in the summer and refreezes again in the winter.The northern part of Alaska is covered in lakes—thousands of them—and most of these are what we call thaw lakes.T-h-a-w.Thaw lakes.I'm gonna show you a few sketches of them in a minute,so you'll have a good idea of what I'm talking about.So, how these thaw lakes are formed has to do with…OK,it starts with ice wedges.The top part of the ice wedge melts—Should I back up?Ice wedges form when water runs into cracks in the ground,the permafrost,then freezes.You ever see mud after it dries?Dried mud has cracks,because when it dries, it contracts,it shrinks.Well,in winter,permafrost behaves similarly.It shrinks in winter,because it freezes even more thoroughly then,and as it shrinks,it forms deep,deep cracks.Then in the summer,when the active layer—the top layer of the permafrost—melts,the melt water runs into those cracks in the permafrost,then freezes again—because that ground,the ground beneath the active layer,is still below freezing.So,you have wedges of ice in the permafrost.Now the ice wedges widen the original cracks in the permafrost,because water expands when it freezes.All right?OK,then in autumn,the active layer on top freezes again.Then in winter,the permafrost starts contracting again and the cracks open up even wider.So the next summer,when the active layer melts again and flows into the widened cracks…and…freezes…it makes the cracks even wider.So it’s sort of a cycle through which the cracks and the wedges grow wider and wider.So when the ice wedge reaches a certain size,its top part—in the active layer—turns into a little pond when it melts in the summer.And that's the beginning of your thaw lake.[pause]There are thousands of them in northern Alaska.One of the most fascinating things about these lakes—and this is important—is that they mostly havethe same shape.Like an elongated oval,or egg shape.And what's more,all the ovals are oriented in the same way.Here's an idea of what they look like,what the landscape looks like from an aerial view,with the lakes side by side.There's been considerable research done to try to figure out what causes them to be shaped and oriented this way.We know that the shape and orientation are caused by the way the lakes grow once they're formed,but the question is,what makes them grow this way?One theory sees winds as the cause.This region of Alaska has strong winds that blow perpendicular to the lakes.What happens is,wind blows straight into the longer side of the lakes.Now,wouldn’t that erode the lake bank in that direction?The same direction as the wind?Well…no.Actually,what happens is that the waves caused by the winds build a sorta protective layer of sediment—it's called a“protective shelf”—along the bank of the lake directly in front of them;so that bank is shielded from erosion,and the waves are diverted to the sides,to the left and to the right,and that’s why the left and the right banks start eroding.Get it?The bank straight ahead is protected,but the lake currents--the waves--erode the banks to the sides.That's the current model,um,the wind erosion model,which is generally accepted.But,there's a new theory that says that[deliberately]thaw slumping,not wind,is what shapes the thaw lakes.Thaw slumping,um…OK.Sometimes,in the summer,the temperature rises pretty quickly.So the active layer of permafrost thaws faster than the water can drain from the soil.So the sides of the thaw lakes get,like,mushy,and slump,or slide,into the lake.Then,the lake water spreads out more,and the lake gets bigger,OK?Also,in that part of Alaska,the terrain is gently sloped,so the lakes are all on an incline.Here.Now,this is an exaggeration of the angle—the hill isn't this steep—butsee how with the lake's banks,the side that is farther downhill…it's smaller,lower. This short bank thaws faster than the tall one does,so it falls into the lake—it slumps, much more and much faster than the other bank.When the short banks of many lakes slump,they move farther downhill and the lakes grow—all in the same downhill direction.This is a new theory,so it hasn't been tested much yet.In field studies,when we've looked at the banks of these thaw lakes,there's not much evidence of slumping. We'd expect to see cliff-like formations there,from the slumping,but we haven't really found many of those.题目1.What is the main purpose of the lecture?[Click on two answers.]A.To contrast how different kinds of thaw lakes growB.To explain why a new theory of thaw lakes is gaining acceptanceC.To explain how processes in permafrost lead to the formation of thaw lakesD.To describe two competing theories about the growth of thaw lakes2.The professor explains thaw lake formation as a cycle of events that occur repeatedly.Summarize this cycle,starting with the event filled in below.[Click on a sentence.Then drag it to the space where it belongs.The first one is done for you. One sentence will not be used]A.Meltwater flows into cracks in permafrostB.Ice wedges inside permafrost completely meltC.Freezing water expands cracks in permafrostD.Ice in the active layer melts as temperatures riseE.Permafrost shrinks and cracks as temperatures drop..3.What is the significance of the'protective shelf'discussed by the professor?A.It prevents the slumping of lake banks.B.It shields the lake surface from strong winds.C.It redirects the waves to lake banks that do not face the wind.D.It allows the lakes to grow in the same direction as the wind blows.4.According to the thaw slumping model,which side of a thaw lake grows fastest?A.The side where the bank is shortestB.The side least exposed to windC.The side that is at the highest elevationD.The side opposite the protective shelf5.What is the professor's opinion of the thaw slumping model?A.He thinks it was urgently needed.B.He is not convinced that it has a firm basis.C.He thinks it would be better if it were simplified.D.He does not think it is very different from the old model.6.Why does the professor say this:You ever see mud after it dries?A.He wants some information from the students.B.He thinks that the students may find an example helpful.C.He realizes that he forgot to mention an important topic.D.He wants to point out an important difference between frozen ground and dry ground.答案CD EDACB C A B B译文听一段地质学的讲座。

为了帮助大家高效备考托福，为大家带来托福TPO49口语Task3阅读文本+听力文本+题目+满分范文，希望对大家备考有所帮助。

托福TPO49口语Task3阅读文本： Make Textbook List Available Earlier Students always have to wait until the beginning of the semester to find out which textbooks they will need for their new courses. But since a lot of students register early for their courses, I think that the list for each course should be available immediately at the time of registration.This would give students more time to shop around to find less expensive textbooks. And it would also allow them to start work on the reading for their new courses early. Alexandra Brown 托福TPO49口语Task3听力文本： Narrator: Now listen to two students discussing the letter. Man: Hey, did you see Alexandra’s letter? Girl: Yeah, what do you think? Man: Well, it’s great. She really makes some good points, like the thing with the university bookstore is, if you buy a brand new textbook, it can be pretty expensive and they usually have only a few used textbooks around. They’re cheaper of course, but they sell out quickly. Girl: That’s true. Man: So this would give students time to look around on their own. You know, maybe they could find the books they need online, get books a few months ahead of time using the internet. Girl: I agree. Man: So this way students might be able to save a little money. Girl: Right, so what do you think about the second point, about the reading assignment? Man: I agree with that, too. It just makes a lot of sense, because things get really busy when the semester first starts and it can be hard to find time to keepup with all of the assignments, but students usually have some free time right before the start of the semester. Girl: So we’d have a good opportunity to do some preparation. Man: Exactly. 托福TPO49口语Task3题目： The man expresses his opinion about the proposal described in the letter. Briefly summarize the proposal. Then state his opinion about the proposal and explain the reasons he gives for holding that opinion. 托福TPO49口语Task3满分范文： In the letter, Alexandra proposes the school to offer the list of textbooks needed for each course earlier. In this way, students can have more time to find cheaper textbooks and start working on their new courses early. In the conversation, the man supports her proposal. The man states that brand new textbooks are usually expensive and the used one, which are much cheaper, sell out quickly. And if the book list are available earlier, students may be able to get textbook online with less money. In addition, the man agree that at the beginning of each semester, students are often quite busy, hard to keep up with all the assignments. If they can have the textbooks earlier, they may have more time to make preparation ahead of the semester. 以上是给大家整理的托福TPO49口语Task3阅读文本+听力文本+题目+满分范文，希望对你有所帮助!。

为了帮助大家高效备考托福，为大家带来托福TPO49口语Task6听力文本+题目+满分范文，希望对大家备考有所帮助。

托福TPO49口语Task6听力文本： Narrator: Listen to part of a lecture in a biology class. Professor: So of course many animals live in groups with others of their species. And there are benefits to living together in groups. It can help animals survive. But there are also certain disadvantages. So today we are going to talk about two disadvantages of living in groups for animals. One disadvantage is that animals that live in groups may be more visible to predators. If there's a big group of animals, predators are more likely to spot them than they would an individual animal on its own. So sometimes animals in a group may be more vulnerable to being captured by predators. For instance, Sardines, really small fish, swim in groups, and other larger ocean animals, like some kind of whales, eat them. So while a whale probably wouldn’t notice one Sardine, it would see a group of Sardines very easily and thus be able to capture them for food. Another disadvantage has to do with caring for the young. In a large group, there are a lot of young animals around and it can be difficult for animals to find or identify their own young. And they may end up taking care of other animals to young instead. So their own young may not get the care they need. For example, some bats live in caves. And with one type of bat, millions of them live together in the same cave. And with young bats so crowded together in the cave. It's sometimes hard for a mother bat to find her babies. So when a mother bat returns from finding food to feed her babies, she might end up feeding the babies of another mother bat, meaning her own babies don’t get fed. 托福TPO49口语Task6题目： Using points and examples from the lecture, explain two disadvantages of living in groups for animals. 托福TPO49口语Task6满分范文： The lecture is focusing on two disadvantages of living in a group for animals. One disadvantage is that animals living in groups are more visible and vulnerable to predators. Take sardines as an example. They swim in groups and they are prey for some large animals such as whales. Although it may be hard for a whale to notice one little Sardine, it is able to see a group of them and capture them for food. Another disadvantage is that living in groups set great barriers for animals to identify their own young and thus have them in good care. For example, one type of bats live togetherin the same cave with millions of them. With too much bats in the same cave, a mother bat may find it’s hard to find her own baby and she may end up feeding the babies of another mother bat, leaving her own babies with no food. 以上是给大家整理的托福TPO49口语Task6听力文本+题目+满分范文，希望对你有所帮助!。