托福听力资料托福tpo15听力文本 (2)
历年托福听力真题
历年托福听力真题历年托福听力真题精选Conversation 1女生想加入爵士乐队，尽管专业是其他但音乐是爱好，想继续保持。
但教授的team已经不缺人了，教授建议她自己多关于Website，学生band会更新信息。
-TPO部分对应参考(社团生活TPO11-C1/TPO15-C1/TPO26-C1) -TPO对应词汇校内工作，课外活动及寻找经济援助：Letterof reference/recommendationCompetitiveBenefitfuture careerFieldresearchCollectdata for papersWaiter,waitress，BabysitterWorkat the libraryQualification资格,qualified 合格的Resume,CVfinancialaid经济援助ScholarshipFellowshipTeachingassistantship 助教奖学金Researchassistantship 研究奖学金Grant助学金Loan 贷款Need-based以需求为基础Merit-based以优秀为基础Studentunion 学生会Clubs俱乐部Membership成员资格CareerserviceLecture 1自然科学类。
讲矮行星是如何形成的，与行星的区别。
一个是ejection theory，跟gravity的原因有关。
第二个就是吸收的material 无法发光，屏幕给了这两个theory的名词提醒。
-TPO部分对应参考(天文学TPO18-L1/TPO24-L4/T13-L4)-参考背景Sufficient internal pressure, caused by the body's gravitation, will turn abody plastic, andsufficient plasticity will allow high elevations to sink and hollows to fillin, a process known as gravitational relaxation. Bodies smaller than a fewkilometers are dominated by non-gravitational forces and tend to have anirregular shape. The Saturnian moon Methone, at around 3 km in diameter, is a roundedbut tidally elongated egg-shape. Larger objects, where gravitation issignificant but not dominant, are "potato" shaped; the more massivethe body is, the higher its internal pressure and the more rounded its shape,until the pressure is sufficient to overcome its internal compressive strength and it achieves hydrostatic equilibrium. At this point a body is as round as it is possible to be, given itsrotation and tidal effects, and is an ellipsoid in shape. This is the defining limit of a dwarf planet.When an object is in hydrostatic equilibrium, a global layer of liquidcovering its surface would form a liquid surface of the same shape as the body,apart from small-scale surface features such as craters and fissures. If thebody does not rotate, it will be a sphere, but the faster it does rotate, themore oblate or even scalene it becomes. However, if such a rotating body were to be heated until itmelted, its overall shape would not change whenliquid. The extreme example ofa non-spherical body in hydrostatic equilibrium is Haumea, whichis twice as long along its major axis as it is at the poles. If the body has amassive nearby companion, then tidal forces come into effect as well,distorting it into a prolate spheroid. An example of this is Jupiter's moon Io, which is the most volcanically active bodyin the Solar System due to effects of tidal heating. Tidal forces also cause a body's rotationto gradually become tidally locked, such that it always presents the same faceto its companion. An extreme example of this is the Pluto–Charon system, whereboth bodies are tidally locked to each other. Earth's Moon is also tidally locked, as are many satellites of the gas giants.Lecture 2社会科学类。
剑桥15-test3 -part 2 原文
Cambridge IELTS 15 Test 3 Audio scriptPART 2 (Q11-16)PRESENTER: My guest on the show today is Alice Riches who started the Street Play Scheme where she lives in Beechwood Road. For those of you that don’t already know - Street Play involves local residents closing off their street for a few hours so that children have chance to play in the street safely. She started it in her own street, Beechwood Road, and the idea caught on, and there are now Street Play Scheme all over the city. So when did you actually start the scheme, Alice?ALICE: Well, I first had the idea when my oldest child was still a toddler, so that’s about six years ago now – but it tool at least two years of campaigning before we were actually able to make it happen. So the scheme’s been up and running for three years now. [Q11] We’d love to be able to close our road for longer –for the whole weekend, from Saturday morning until Sunday evening, for example. At the moment it’s just once a week. But when we started it was only a month. [Q12] But we’re working on it.PRESENTER: So what actually happens when Beechwood Road is closed?ALICE: We have volunteer wardens, mostly parents but some elderly residents too, who block off our road at either end. The council have provided special signs but there’s always a volunteer there to explain what’s happening to a ny motorists. [Q13] Generally, they’re fine about it –we’ve only had to get the police involved once or twice.Now I should explain that the road isn’t completely closed to cars. But only residents’ cars are allowed. If people really need to get in or ou r of Beechwood Road, it’s not a problem – as long as they drive at under 20 kilometres per hour. [Q14] But most people just decide not to use their cars during this time, or they park in another street. The wardens are only there to stop through traffic.PRESENTER: So can anyone apply to get involved in Street Play?ALICE: Absolutely – we want to include all kids in the city –especially those who live on busy roads. It’s here that demand is greatest. [Q15] Obviously, there isn’t such demand in wealthierareas where the children have access to parks or large gardens –or in the suburbs where there are usually more places for children to play outside.I’d recommend that anyone listening who likes the idea should just give it a go. We’ve been surprised by th e positive reaction of residents all over the city. And that’s not just parents. There are always a few who complain but they’ve very happy to see children out on the street – even if it does get quite noisy. [Q16]PART 2 (Q17-20)ALICE: There have been so many benefits of Street Play for the kids. Parents really like the fact that the kids are getting fresh air instead of sitting staring at a computer screen, even of they’re not doing anything particularly energetic. And of course it’s great that kids can play with their friends outside without being supervised by their parents – but for me the biggest advantage is that kids develop confidence themselves to be outside without their parents. [Q17] The other really fantastic thing is that children get to know the adults in the street –it’s like having a big extended family. [Q18]PRESENTER: It certainly does have a lot of benefits. I want to move on now and ask you about a related project in King Street.ALICE: Right. Well this was an experiment I was involved in where local residents decided to try and reduce the traffic along King Street, which is the busiest main road in our area, by persuading people not to use their cars for one day. We thought about making people pay more for parking – but we decided that would be really unpopular – so instead we just stopped people from parking on King Street but left the other car parks open.It was surprising how much of a difference all this made. As we’d predicted, air quality was significantly better but what I had n’t expected was how much quieter it would be – even with the buses still running. [Q19] Of course everyone said they felt safer but we were actually amazed that sales in the shops went up considerably that day –we thought there’d be fewer people out shopping – not more. [Q20]PRESENTER: Good morning. That’s really interesting so the fact that…。
托福TPO15听力Conversation2文本+题目+答案解析
为了帮助大家高效备考托福，为大家带来托福TPO15听力Conversation2文本+题目+答案解析，希望对大家备考有所帮助。
托福TPO15听力Conversation2文本 Narrator: Listen to part of a conversation between a student and her biology professor. Professor: Hi, Samantha, how did your track meet go? Student: Great! I placed first in one race and third in another. Professor: Congratulations, you must practice a lot. Student: Three times a week pre-season, but now that we are competing every weekend. We practice six days a week from 3:30 to 5. Professor: Athletics places a heavy demand on your time, don’t they? Student: Yeah, but I really love competing, so… Professor: You know, I played soccer in college and my biggest challenge, and I didn’t always succeed, was getting my studying in during soccer season. Are you having a similar? Student: No. I really do make time to study, and I actually study more for this class than I do for all my other classes. But I didn’t see the grade I expected on my mid-term exam which is why I came by. Professor: Well, you didn’t do badly on the exam but I agree it did not reflect your potential. I say this because your work on the lab project was exemplary. I was so impressed with the way you handled the microscope and the samples of onion cells and, well, how careful you observed and diagramed and interpreted each stage of cell division, and I don’t think you could have done that if you hadn’t understood the chapter. I mean, it seemed you really had a good understanding of it. Student: I thought so, too. But I missed some questions about cell division on the exam. Professor: So, what happened? Student: I just sort of blanked out, I guess. I had a hard time remembering details. It was so frustrating. Professor: All right. Let’s back up. You say you studied. Where? At home? Student: At my kitchen table, actually. Professor: And that’s supposed to be a quiet environment? Student: Not exactly. My brother and parents try to keep it down when I’m studying but the phone pretty much rings off the hook, so. Professor: So you might try a place with fewer distractions, like, the library. Student: But the library closes at midnight and I like to study all night before a test. You know, so everything is fresh in my mind. I studied six straight hours the night before the mid-term exam. That’s why I expected to do so much better. Professor: Oh, OK. You know that studying six consecutive hours is not equivalent to studying one hour a day for six days. Student: It isn’t? Professor: No, there’s a research that shows that after an hour of intensive focus, your brain needs a break. It needs to, you know, shift gears a little. Your brain’s ability to absorb information starts to decline after about the first hour. So if you are dealing with a lot of new concepts and vocabulary, anyway, if you just review your notes even twenty minutes a day, it’d be much better than waiting until the night before the exam to try and absorb all those details. Student: Oh, I didn’t realize. Professor: Think of your brain as a muscle. If you didn’t practice regularly with your track team, and then try to squeeze in three weeks’ worth of running practice the day before a track meet, how well do you think you will perform in the races? 托福TPO15听力Conversation2题目 1.Why does the woman go to see her professor? A. To tell him about an athletic achievement. B. To find out the best approach to studying for a test. C. To ask a question about a laboratory project.。
TPO15听力解析
TPO15 listening 问题解析注：问题中红色标记词汇为解题突破点和关键词。
Section 1TPO15-L1 Conversation 11. Why does the student go to the campus newspaper office?O To turn in outlines of possible articlesO To find out when his article will be printed in the newspaperO To find out if he got a position as a reporterO To get help with an assignment for his journalism class答案：C解析：男学生报名做reporter，写好的outline一周前已经提交，但是没有收到答复，他来看一下情况。
原文如下：I sent them in about a week ago, but I haven't heard anything back yet, so, so I thought I'd stop by and see, but I guess you haven't looked at them yet2. Why does the student want to write for the campus newspaper?O He wants to earn some money.O He wants to learn about the newspaper business.O He wants to share his enthusiasm for physics.O He thinks the experience will be valuable.答案：D解析：男学生知道当reporter是没有报酬的，但是这有利于他写个人经历，比较重要。
托福备考托福阅读34套TPO样题+解析+译文15--2 Mass Extinctions物种灭绝
托福考试 复习托福阅读TPO15(试题+答案+译文)第2篇:Mass Extinctions物种灭绝托福阅读原文【1】Cases in which many species become extinct within a geologically short interval of time are called mass extinctions. There was one such event at the end of the Cretaceous period(around 70 million years ago). There was another, even larger, mass extinction at the end of the Permian period (around 250 million years ago). The Permian event has attracted much less attention than other mass extinctions because mostly unfamiliar species perished at that time.【2】The fossil record shows at least five mass extinctions in which many families of marine organisms died out. The rates of extinction happening today are as great as the rates during these mass extinctions. Many scientists have therefore concluded that a sixth great mass extinction is currently in progress.【3】What could cause such high rates of extinction? There are several hypotheses, including warming or cooling of Earth, changes in seasonal fluctuations or ocean currents, and changing positions of the continents. Biological hypotheses include ecological changes brought about by the evolution of cooperation between insects and flowering plants or of bottom-feeding predators in the oceans. Some of the proposedmechanisms required a very brief period during which all extinctions suddenly took place; other mechanisms would be more likely to have taken place more gradually, over an extended period, or at different times on different continents. Some hypotheses fail to account for simultaneous extinctions on land and in the seas. Each mass extinction may have had a different cause.Evidence points to hunting by humans and habitat destruction as the likely causes for the current mass extinction.【4】American paleontologists David Raup and John Sepkoski, who have studied extinction rates in a number of fossil groups, suggest that episodes of increased extinction have recurred periodically, approximately every 26 million years since the mid-Cretaceous period. The late Cretaceous extinction of the dinosaurs and ammonoids was just one of the more drastic in a whole series of such recurrent extinction episodes. The possibility that mass extinctions may recur periodically has given rise to such hypotheses as that of a companion star with along-period orbit deflecting other bodies from their normal orbits, making some of them fall to Earth as meteors and causing widespread devastation upon impact.【5】Of the various hypotheses attempting to account for the late Cretaceous extinctions, the one that has attracted the most attention in recent years is the asteroid-impact hypothesis first suggested by Luis andWalter Alvarez. According to this hypothesis, Earth collided with an asteroid with an estimated diameter of 10kilometers, or with several asteroids, the combined mass of which was comparable. The force of collision spewed large amounts of debris into the atmosphere, darkening the skies for several years before the finer particles settled. The reduced level of photosynthesis led to a massive decline in plant life of all kinds, and this caused massive starvation first of herbivores and subsequently of carnivores. The mass extinction would have occurred very suddenly under this hypothesis.【6】One interesting test of the Alvarez hypothesis is based on the presence of the rare-earth element iridium (Ir).Earth’s crust contains very little of this element, but most asteroids contain a lot more. Debris thrown into the atmosphere by an asteroid collision would presumably contain large amounts of iridium, and atmospheric currents would carry this material all over the globe. A search of sedimentary deposits that span the boundary between the Cretaceous and Tertiary periods shows that there is a dramatic increase in the abundance of iridium briefly and precisely at this boundary. This iridiumanomaly offers strong support for the Alvarez hypothesis even though no asteroid itself has ever been recovered.【7】An asteroid of this size would be expected to leave an immense crater, even if the asteroid itself was disintegrated by the impact. The intenseheat of the impact would produce heat-shocked quartz in many types of rock. Also, large blocks thrown aside by the impact would form secondary craters surrounding the main crater.To date, several such secondary craters have been found along Mexico’s Yucatan Peninsula, and heat-shocked quartz has been found both in Mexico and in Haiti.A location called Chicxulub, along the Yucatan coast, has been suggested as the primary impact site.托福阅读试题1.Paragraph 1 supports which of the following statements about mass extinctions?A.They take place over a period of 70 million years.B.They began during the Cretaceous period.C.They eliminate many animal species that exist at the time they occur.D.They occur every 250 million years.2.According to paragraph 2, scientists base their belief that a mass extinction is going on at present on which of the following?A.The speed with which mass extinctions are happening today is similar to the speed of past extinctions.B.The number of species that have died out since the last extinction event is extremely large.C.Mass extinctions occur with regularity and it is time for another one.D.Fossil records of many marine species have disappeared.3.The word extended in the passage is closest in meaning toA.specific.B. unlimited.C.reasonable.D. long.4.According to paragraph 3, each of the following has been proposed asa possible cause of mass extinctions EXCEPTA.habitat destruction.B.continental movement.C.fierce interspecies competition.D.changes in Earth's temperature.5.Paragraph 3 supports which of the following ideas about mass extinctions?A.Scientists know the exact causes of most mass extinctions.B.Mass extinctions are unlikely to happen again in the future.C.Insects, flowering plants, and bottom-feeding predators in the oceans tend to be the first organisms to disappear during episodes of mass extinctions.D.Some mass extinctions occurred on land and in the seas at the same time.6.Which of the sentences below best expresses the essential information in the underlined sentence （Paragraph 4）in the passage? Incorrect choices change the meaning in important ways or leave out essential information.A.Based on their studies of extinction rates of numerous fossil groups, paleontologists David Raup and John Sepkoski have determined that mass extinctions occur about every 26 million years.B.David Raup and John Sepkoski studied extinction rates of numerous fossil groups and suggest that mass extinctions during the Cretaceous period continued for 26 million years.C.Studies that paleontologists David Raup and John Sepkoski conducted of various fossil groups have revealed that extinction rates have increased over the past 26 million years.D.The studies conducted by paleontologists David Raup and John Sepkoski of the fossil remains of species suggest that the extinction rate of species started to increase by the middle of the Cretaceous period. 7.According to paragraph 4, what aspect of extinction episodes does the companion-star hypothesis supposedly clarify?A.Their location.B.Their frequency.C.Their duration.D.Their severity.8.The phrase account for in the passage(Paragraph 5)is closest in meaning toA.describe.B.challenge.C.explain.D.test.9.According to paragraph 6, what made iridium a useful test of the Alvarez hypothesis?A.Its occurrence in a few locations on Earth against several locations on other planets.B.Its occurrence in limited quantities on Earth against its abundance in asteroids.C.Its ability to remain solid at extremely high temperatures.D.Its ease of detection even in very small amounts.10.In stating that no asteroid itself has ever been recovered, the author emphasizes which of the following?A.The importance of the indirect evidence for a large asteroid.B.The fact that no evidence supports the asteroid impact hypothesis.C.The reason many researchers reject the Alvarez hypothesis.D.The responsibility of scientists for not making the effort to discover the asteroid itself.11.The word intense（Paragraph 7）in the passage is closest in meaningtoA.sudden.B.unusual.C.immediate.D. extreme.12.What is the purpose of paragraph 7 in the passage?A.It proposes a decisive new test of the Alvarez hypothesis.B.It presents additional supporting evidence for the Alvarez hypothesis.C.It explains why evidence relating to the Alvarez hypothesis is hard to find.D.It shows how recent evidence has raised doubts about the Alvarez hypothesis.13. Look at the four squares [■] that indicate where the following sentence could be added to the passage. Where would the sentence best fit? In general, it is believed that these two extinctions resulted from drastic environmental changes that followed meteorite impacts or massive volcanic eruptions.■Cases in which many species become extinct within a geologically short interval of time are called mass extinctions. ■There was one such event at the end of the Cretaceous period (around 70 million years ago). ■There was another, even larger, mass extinction at the end of the Permian period (around 250 million years ago). ■The Permian event has attracted muchless attention than other mass extinctions because mostly unfamiliar species perished at that time.14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.There have been many attempts to explain the causes of mass extinctions.A.Asteroid impacts, evolutionary developments, and changes in Earth's climate and in the positions of the continents have all been proposed as possible causes of mass extinctions.B.Researchers have observed 26-million-year cycles in extinction rates of a number of fossil groups that could all be attributed to the same cause.C.According to the Alvarez hypothesis, much of the iridium originally present on Earth was thrown into the atmosphere as a result of an asteroid impact that also caused a mass extinction.D.The unusual distribution of iridium on Earth and the presence of craters and heat-shocked quartz are central to the theory that an asteroid impact caused the late Cretaceous event.E.The collision between Earth and a large asteroid resulted in massive damage and generated enough heat to cause irreversible changes inEarth's atmosphere.F.There was a particularly large mass extinction that occurred around 250 million years ago at the end of the Permian period, whose cause could not be determined.托福阅读答案1.以mass extinctions做关键词定位至第一句，说大量生物在短时间内灭绝的这种现象叫做大灭绝事件，C是原文的同义替换，所以是正确答案。
托福听力TPO学习宝典
Solution No.2
TheEffect of mountains and lands,i.e. Topography
Lake-effect snow
E.G. Great Lakes
The forming of clouds
The forming of snow
Closing
Talk to the boss
TPO18conversation1student—administrator—help
Structure
Student
Librarian
Opening
Transfer from Chicago
Interested intheprogram
International studies
TPO 20 conversation 1 Student—Librarian—help
Structure
Student
Librarian
Opening
Problem
Asked to return the book
To keep the book for thesis
Backgrounddetails
Prominentalumni
Advanced math course
TPO 21conversation 2student—professor—question
Structure
Student
Librarian
Opening
Learn a lot from the lecture
Work in the field
TPO文章结构—conversation
托福TPO15
TPO15-1-1 原文：A Warm-Blooded TurtleWhen it comes to physiology, the leatherback turtle is, in some ways, more like a reptilian whale than a turtle. It swims farther into the cold of the northern and southern oceans than any other sea turtle, and it deals with the chilly waters in a way unique among reptiles.A warm-blooded turtle may seem to be a contradiction in terms. Nonetheless, an adult leatherback can maintain a body temperature of between 25 and 26°C (77-79°F) in seawater that is only 8°C (46.4°F). Accomplishing this feat requires adaptations both to generate heat in the turtle’s body and to keep it from escaping into the surrounding waters. Leatherbacks apparently do not generate internal heat the way we do, or the way birds do, as a by-product of cellular metabolism. A leatherback may be able to pick up some body heat by basking at the surface; its dark, almost black body color may help it to absorb solar radiation. However, most of its internal heat comes from the action of its muscles.Leatherbacks keep their body heat in three different ways. The first, and simplest, is size. The bigger the animal is, the lower its surface-to-volume ratio; for every ounce of body mass, there is proportionately less surface through which heat can escape. An adult leatherback is twice the size of the biggest cheloniid sea turtles and will therefore take longer to cool off. Maintaining a high body temperature through sheer bulk is called gigantothermy. It works for elephants, for whales, and, perhaps, it worked for many of the larger dinosaurs. It apparently works, in a smaller way, for some other sea turtles. Large loggerhead and green turtles can maintain their body temperature at a degree or two above that of the surrounding water, and gigantothermy is probably the way they do it. Muscular activity helps, too, and an actively swimming green turtle may be 7°C (12.6°F) warmer than the waters it swims through.Gigantothermy, though, would not be enough to keep a leatherback warm in cold northern waters. It is not enough for whales, which supplement it with a thick layer of insulating blubber (fat). Leatherbacks do not have blubber, but they do have a reptilian equivalent: thick, oil-saturated skin, with a layer of fibrous, fatty tissue just beneath it. Insulation protects the leatherback everywhere but on its head and flippers. Because the flippers are comparatively thin and blade-like, they are the one part of the leatherback that is likely to become chilled. There is not much that the turtle can do about this without compromising the aerodynamic shape of the flipper. The problem is that as blood flows through the turtle’s flippers, it risks losing enough heat to lower the animal’s central body temper ature when it returns. The solution is to allow the flippers to cool down without drawing heat away from the rest of the turtle’s body. The leatherback accomplishes this by arranging the blood vessels in the base of its flipper into a countercurrent exchange system.In a countercurrent exchange system, the blood vessels carrying cooled blood from the flippers run close enough to the blood vessels carrying warm blood from the body to pick up some heat from the warmer blood vessels; thus, the heat is transferred from the outgoing to the ingoing vessels before it reaches the flipper itself. This is the same arrangement found in an old-fashioned steam radiator, in which the coiled pipes pass heat back and forth as watercourses through them. The leatherback is certainly not the only animal with such an arrangement; gulls have a countercurrent exchange in their legs. That is why a gull can stand on an ice floe without freezing.All this applies, of course, only to an adult leatherback. Hatchlings are simply too small to conserve body heat, even with insulation and countercurrent exchange systems. We do not know how old, or how large, a leatherback has to be before it can switch from a cold-blooded to a warm-blooded mode of life. Leatherbacks reach their immense size in a much shorter time than it takes other sea turtles to grow. Perhaps their rush to adulthood is driven by a simple need to keep warm.---------------------------------------------------------------------------------------------------------------Paragraph 1: When it comes to physiology, the leatherback turtle is, in some ways, more like a reptilian whale than a turtle. It swims farther into the cold of the northern and southern oceans than any other sea turtle, and it deals with the chilly waters in a way unique among reptiles.1. The phrase “unique among” in the passage is closest in meaning to○natural to○different from all other○quite common among○familiar to2. What can be inferred about whales from paragraph 1?○They are considered by some to be reptiles.○Their bodies are built in a way that helps them manage extremely cold temperatures.○They are distantly related to leatherback turtles.○They can swim farther than leatherback turtles.Paragraph 2: A warm-blooded turtle may seem to be a contradiction in terms. Nonetheless, an adult leatherback can maintain a body temperature of between 25 and 26°C (77-79°F) in seawater that is only 8°C (46.4°F). Accomplishing this feat requires adaptations both to generate heat in the turtle’s body and to keep it from escaping into the surrounding waters. Leatherbacks apparently do not generate internal heat the way we do, or the way birds do, as a by-product of cellular metabolism. A leatherback may be able to pick up some body heat by basking at the surface; its dark, almost black body color may help it to absorb solar radiation. However, most of its internal heat comes from the action of its muscles.3. The word “feat” in the passage is closest in meaning to○remarkable achievement○common transformatio n○daily activity○complex solution4. Paragraph 2 mentions all of the following as true about the body heat of adult leatherback turtles EXCEPT:○Their muscles produce heat for maintaining body temperature.○Their dark bodies help trap solar radiation.○Their cellular metabolism produces heat as a by-product.○Basking at the water’s surface helps them obtain heat.Paragraph 3: Leatherbacks keep their body heat in three different ways. The first, and simplest, is size. The bigger the animal is, the lower its surface-to-volume ratio; for every ounce of body mass, there is proportionately less surface through which heat can escape. An adult leatherback is twice the size of the biggest cheloniid sea turtles and will therefore take longer to cool off. Maintaining a high body temperature through sheer bulk is called gigantothermy. It works for elephants, for whales, and, perhaps, it worked for many of the larger dinosaurs. It apparently works, in a smaller way, for some other sea turtles. Large loggerhead and green turtles can maintain their body temperature at a degree or two above that of the surrounding water, and gigantothermy is probably the way they do it. Muscular activity helps, too, and an actively swimming green turtle may be 7°C (12.6°F) warmer than the waters it swims through.5. The word “bulk” in the passage is closest in meaning to○strength○effort○activity○massParagraph 4: Gigantothermy, though, would not be enough to keep a leatherback warm in cold northern waters. It is not enough for whales, which supplement it with a thick layer of insulating blubber (fat). Leatherbacks do not have blubber, but they do have a reptilian equivalent: thick, oil-saturated skin, with a layer of fibrous, fatty tissue just beneath it. Insulation protects the leatherback everywhere but on its head and flippers. Because the flippers are comparatively thin and blade-like, they are the one part of the leatherback that is likely to become chilled. There is not much that the turtle can do about this without compromising the aerodynamic shape of the flipper. The problem is that as blood flows through the turtle’s flippers, it risks losing enough heat to lower the animal’s central body temperature when it returns. The solution is to allow the flippers to cool down without drawing heat away from the rest of the turtle’s body. The leatherback accomplishes this by arranging the blood vessels in the base of its flipper into a countercurrent exchange system.6. The word “it” in paragraph 4 refers to○the problem○blood○the turtle○body temperature7. According to paragraph 4, which of the following features enables the leatherback turtle to stay warm?○An insulating laye r of blubber○A thick, oily skin covering fatty tissue○The aerodynamic shape of its flippers○A well-insulated headParagraph 5: In a countercurrent exchange system, the blood vessels carrying cooled blood from the flippers run close enough to the blood vessels carrying warm blood from the body to pick up some heat from the warmer blood vessels; thus, the heat is transferred from the outgoing to the ingoing vessels before it reaches the flipper itself. This is the same arrangement found in an old-fashioned steam radiator, in which the coiled pipes pass heat back and forth as water courses through them. The leatherback is certainly not the only animal with such an arrangement; gulls have a countercurrent exchange in their legs. That is why a gull can stand on an ice floe without freezing.8. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.○In a turtle's countercurrent exchange system, outgoing vessels lie near enough to ingoing ones that heat can be exchanged from the former to the latter before reaching the turtle's flippers.○Within the turtle's flippers, there is a countercurrent exchange system that allows colder blood vessels to absorb heat from nearby warmer blood vessels and then return warmed blood to the turtle's body.○In a countercurrent exchange system, a turtle can pick up body heat from being close enough to other turtles, thus raising its blood temperature as it passes them.○When a turtle places its flippers close to its body, it is able to use its countercurrent exchange system to transfer heat from the warmer blood vessels in its body to the cooler blood vessels in its flippers.9. Why does the author mention old-fashioned steam radiator in the discussion of countercurrent exchange systems?○To argue that a turtle's central heating system is not as highly evolved as that of other warmblooded animals○To provide a useful comparison with wh ich to illustrate how a countercurrent exchange system works○To suggest that steam radiators were modeled after the sophisticated heating system of turtles○To establish the importance of the movement of water in countercurrent exchange systems10. The phrase “courses through” in the passage is closest in meaning to○rises through○heats up in○runs through○collects inParagraph 6: All this applies, of course, only to an adult leatherback. Hatchlings are simply too small to conserve body heat, even with insulation and countercurrent exchange systems. We do not know how old, or how large, a leatherback has to be before it can switch from a cold-blooded to a warm-blooded mode of life. Leatherbacks reach their immense size in a much shorter time than it takes other sea turtles to grow. Perhaps their rush to adulthood is driven by a simple need to keep warm.11. According to paragraph 6, which of the following statements is most accurate about young leatherback turtles?○They lack the countercurrent excha nge systems that develop in adulthood.○Their rate of growth is slower than that of other sea turtles.○They lose heat easily even with insulation and countercurrent exchange systems.○They switch between cold-blooded and warm-blooded modes throughout their hatchling stage.Paragraph 3: Leatherbacks keep their body heat in three different ways. The first, and simplest, is size. The bigger the animal is, the lower its surface-to-volume ratio; for every ounce of body mass, there is proportionately less surface through which heat can escape. An adult leatherback is twice the size of the biggest cheloniid sea turtles and will therefore take longer to cool off. Maintaining a high body temperature through sheer bulk is called gigantothermy. ■It works for elephant s, for whales, and, perhaps, it worked for many of the larger dinosaurs. ■It apparently works, in a smaller way, for some other sea turtles. ■Large loggerhead and green turtles can maintain their body temperature at a degree or two above that of the surrou nding water, and gigantothermy is probably the way they do it. ■Muscular activity helps, too, and an actively swimming green turtle may be 7°C (12.6°F) warmer than the waters it swims through.12. Look at the four squares [■] that indicate where the follo wing sentence could be added to the passage.However, these animals have additional means of staying warm.Where would the sentence best fit?13. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.Contrary to what we would expect of reptiles, the leatherback turtle is actually warm-blooded.●The leatherback turtle uses a…●The leatherback turtle is…●Leatherbacks have an…Answer Choices○Even though they swim into cold ocean waters,leatherbacks maintain their body heat in much the same way as sea turtles in warm southern oceans do.○The leatherback turtle uses a countercurrent exchange system in order to keep the flippers from drawing heat away from the rest of the body.○The shape of the leatherback turtle's flippers is especially important in maintaining heat in extremely cold northern waters.○The leatherback turtle is able to maintain body heat through sheer size.○Leatherbacks have an insulating layer that can be considered the reptilian version of blubber.○Young leatherbacks often do not survive to adulthood because they are not able to switch from a cold-blooded way of life to a warm-blooded one quickly enough.---------------------------------------------------------------------------------------------------------------参考答案：1. ○22. ○23. ○14. ○35. ○46. ○27. ○28.○19. ○210. ○311. ○312. ○413. The leatherback turtle uses a…The leatherback turtle is…Leatherbacks have an…--------------------------------------------------------------------------------------------------------------- 答案解析：B，词汇题。
托福TPO15口语Task2题目+满分范文
为了帮助大家高效备考托福，为大家带来托福TPO15口语Task2题目+满分范文，希望对大家备考有所帮助。
托福TPO15独立口语Task2题目： Question Do you agree or disagree with the following statement? It is important to remember and learn from the past. Use details and examples to explain your opinion. 托福TPO15独立口语Task2满分范文： I totally agree with this statement that it’s important to remember and learn from the past.We all make mistakes and we all have to remember mistakes. Because mistakes tell us what isn’t right. For example, when I was in the first grade primary school, I took a toy car from another student without informing him. I was too young to know that taking things from others without mentioning isn’t right. Then my teacher helped the other student find this toy car and labeled me as a thieve. I didn’t realize how serious this matter was until my father told me that this was humiliating.I swore to myself that I would never take anything from others without informing the owners. I think this is a valuable lesson and I’ll remember it forever. 以上是给大家整理的托福TPO15口语Task2题目+满分范文，希望对你有所帮助!。
【托福听力资料】托福TPO15 听力文本——Lecture 2
【托福听力资料】托福TPO15 听力文本——Lecture 2众所周知，托福TPO材料是备考托福听力最好的材料。
相信众多备考托福的同学也一直在练习这套材料，那么在以下内容中我们就为大家带来托福TPO听力练习的文本，希望能为大家的备考带来帮助。
TPO 15 Lecture 2 GeologyNarrator: Listen to part of a lecture in a geology class .ProfessorAs geologists, we examine layers of sediment on the Earth’ s surface to approximate the dates of past geologic time periods. Uh... sediment as you know, is material like sand , gravel, fossil fragments that is transported by natural processes like wind , water flow or the movement of glaciers. So sediment is transported and then deposited and it forms layers on the Earth’s surface over time. We examine these layers to learn about different geologic time periods including when they began and ended.For example, from about 1.8 million years ago to around 11 thousand years ago was the Pleistocene Epoch. The Pleistocene Epoch was an ice age. During this Epoch, sediment was made by the kind of erosion and weathering that happens when the climate is colder, and part of those sediments are fossils of plants and animals that lived at that time.The Holocene Epoch followed the Pleistocene Epoch when the Earth ’ s climate warmed up around 11 thousand years ago. The Holocene Epoch is characterized by different sediments, ones that form when the climate is warmer. Because the climate changed, the types of plants and animals changed also. Holocenesediments contain remnants of more recent plants and animals, so it’s prettyeasy to differentiate geologically between these two Epochs.Now there is growing evidence that the presence of humans has altered theEarth so much that a new Epochc of geologic history has begun – the AnthropoceneEpoch, a new human-influenced Epoch. This idea that we’ve entered a newAnthropocene Epoch was first proposed in 2002. The idea is that around the year1800 CE the human population became large enough, around a billion people, thatits activities started altering the environment.This was also the time of the industrial revolution, which brought atremendous increase in the use of fossil fuels such as coal. The exploitation offossil fuels has brought planetwide developments: industrialization,construction, uh, mass transport. And these developments have caused majorchanges like additional erosion of the Earth’s surface and deforestation. Also,things like the damming of rivers , has caused increased sediment production,not to mention the addition of more carbon dioxide and methane in theatmosphere. Naturally all these changes show up in recent sediments. And thesesediments are quite different from pre year 1800 sediment layers.Interestingly there’s some speculation that humans started having a majorimpact on Earth much earlier, about 8000 years ago. That’s when agriculture wasbecoming widespread. Early farmers started clearing forests and livestockproduced a lot of extra methane. But I want to stress this is just a hypothesis.The idea that early humans could have had such a major effect, well I’m just notsure we can compare it with the industrial age.Geologists in the far future will be able to examine the sediment being laiddown today, whereas right now we can say that yes, human impact on the Earth isclear: It’ll be future researchers who have a better perspective and will beable to really draw a line between the Holocene and the Anthropocene Epochs。
托福听力学科分类(完全修正版)(可编辑修改word版)
8
TPO 22 Lecture 2
Faint Young Sun Paradox
Astronomy
9
TPO 24 Lecture 4
Shield Volcanoes on Venus
Astronomy
10
TPO 26 Lecture 3
The Orbits of Comets
Astronomy
ArtHistory
11
TPO 21 Lecture 4
Alice Neel (Artist)
Art History
12
TPO 33 Lecture 4
Renaissance Gardens
ArtHistory
13
TPO 34 Lecture 1
Dada
ArtHistory
14
TPO 15 Lecture 3
Nightcap Oak
Botany
20
TPO 34 Lecture 3
Relationship between Plant and its
Pollinator
Botany
21
TPO 28 Lecture
Plants’ Photoreceptors
Botany
22
TPO 19 Lecture 3
Spartina
Animal & Enviornment
13
TPO 20 Lecture 4
Snowshoe Hare
Animal & Enviornment
14
TPO 07 Lecture 2
Bats' Use of Ultrasound
托福阅读真题第151篇TwoKindsofLizards（答案文章最后）
托福阅读真题第151篇TwoKindsofLizards（答案文章最后）Two Kinds of LizardsParagraph 1：Lizards can be divided into two types according to the way they look for food: sit-and-wait foragers and active foragers. Sit-and-wait lizards normally remain in one spot from which they can survey a broad area. These motionless lizards detect the movement of an insect visually and capture it with a quick run from their observation site. Sit-and-wait lizards may be most successful in detecting and capturing relatively large insects like beetles and grasshoppers. Active foragers, on the other hand, spend most of their time on the ground surface, moving steadily and poking their heads under fallen leaves and into crevices in the ground. These lizards apparently rely largely on chemical cues to detect insects, and they probably seek out local concentrations of prey such as termites. Active foragers appear to eat more insects than do lizards that are sit-and-wait predators. Thus, the different foraging behaviors of lizards lead to differences in their diets, even when the two kinds of lizards occur in the same habitat.1. According to paragraph 1, sit-and-wait foragers and active foragers are different in all of the following EXCEPTO the methods that they primarily use to detect insectsO the number of insects they typically eatO the habitats in which they can be foundO the amount of time they spend moving2. According to paragraph 1, compared to the insects typically consumed by sit-and-wait lizards, insects typically consumed by active lizardsO move more quicklyO are generally found in smaller groupsO are often hidden from viewO spend more time on the surface of the groundParagraph 2：The different foraging modes also have different consequences for lizards regarding their exposure to predators. A lizard that spends 99 percent of its time resting motionless is relatively inconspicuous, whereas a lizard that spends most of its time moving is easily seen. Sit-and-wait lizards are probably most likely to be discovered and captured by predators that are active searchers, whereas widely foraging lizards are likely to be caught by sit-and-wait predators. Because of this difference, foraging modes may alternate at successive levels in the food chain: insects that move about may be captured by lizards that are sit-and-wait foragers, and those lizards may be eaten by active predators, whereas insects that are sedentary are more likely to be discovered by lizards that are active foragers, and those lizards may be caught by sit-and-wait predators.3. In paragraph 2, why does the author contrast the visibility of lizards that remain motionless most of the time with the visibility of lizards that move most of the time？O To show that it is possible for lizards to alternate their foraging modes at successive levels in the food chain O To suggest that sit-and-wait lizards are more likely than active lizards to be attacked by predatorsO To explain why sit-and-wait lizards are more successful than active lizards at preying on insectsO To explain how a lizard's foraging strategy affects the type of predator likely to attack itParagraph 3：The body forms of sit-and-wait foragers mayreflect selective pressures different from those that act on active foragers. Sit-and-wait lizards are often stout bodied, short tailed, and colored to match their background. Many of these species have patterns of different-colored blotches that probably obscure the outlines of the lizard's body as it rests motionless on a rock or a tree trunk. Active foragers are usually slim and elongated with long tails, and they often have patterns of stripes that may produce optical illusions as they move. However, one predator-avoidance mechanism, the ability to break off their tails when they are seized by predators, does not differ among lizards with different foraging modes.4. Paragraph 3 supports which of the following ideas about active-forager lizards？O They are less likely to break off their tails when seized by predators than sit-and-wait lizards are.O They tend to vary widely in their individual colors.O They lack well-developed mechanisms for avoiding predators.O They may be easier to identify when they are not moving than when they are moving.Paragraph 4：What physiological characteristics are necessary to support different foraging modes? The energy requirements of a quick motion that lasts for only a second or two are quite different from those of locomotion that is sustained nearly continuously for several hours. Sit-and-wait lizards and active foragers differ in their relative emphasis on the two ways that most animals use adenosine triphosphate (ATP), a molecule that transports energy within cells for activity, and in how long that activity can be sustained. Sit-and-wait lizards move in brief spurts, and they rely largely on anaerobic metabolism to sustaintheir movements, namely the kind of metabolism that does not use oxygen. Anaerobic metabolism uses glycogen stored in the muscles and produces lactic acid as its end product. It is a way to synthesize ATP quickly (because the glycogen is already in the muscles), but it is not good for sustained activity because the glycogen is quickly exhausted and lactic acid inhibits cellular metabolism. Lizards that rely on anaerobic metabolism can make brief sprints but become exhausted when they are forced to run continuously. In contrast, aerobic metabolism uses glucose that is carried to the muscles by the circulatory system, and it produces carbon dioxide and water as end products. Aerobic exercise can continue for long periods because the circulatory system brings more glucose and carries carbon dioxide away. As a result, active foragers can sustain activity for long periods without exhaustion. Active species of lizards have larger hearts and more red blood cells in their blood than do sit-and-wait species. As a result, each beat of the heart pumps more blood, and that blood carries more oxygen to the tissues of an active species than a sit-and-wait species.5. According to paragraph 4, compared with active lizards, the movements of sit-and-wait lizards areO more suddenO more sustainedO more predictableO more frequent6. According to paragraph 4, all of the following are true about anaerobic metabolism in lizards EXCEPT:O It uses the glycogen in the muscles of lizards.O It produces lactic acid that interferes with metabolism within the cells of lizards.O It allows lizards to maintain their foraging activity over a long period of time.O It allows lizards to run fast for short periods of time.7. Which of the following can be inferred from paragraph 4 about sit-and-wait lizards？O They have less glycogen than active-forager lizards.O They have highly variable heart rates.O They have metabolic systems that do not depend on the efficient removal of carbon dioxide.O They synthesize adenosine triphosphate continuously.8. According to paragraph 4, how are active-foraging lizards and sit-and-wait lizards different from each other？O Sit-and-wait lizards tend to have more red blood cells in their blood than active-foraging lizards do.O Active-foraging lizards' blood carries less oxygen to the tissues than sit-and-wait foraging lizards' blood does.O Sit-and-wait lizards carry out cellular metabolism more efficiently than active-foraging lizards do.O Active-foraging lizards tend to have larger hearts than sit-and-wait lizards do.Paragraph 3：The body forms of sit-and-wait foragers may reflect selective pressures different from those that act on active foragers. Sit-and-wait lizards are often stout bodied, short tailed, and colored to match their background. ■Many of these species have patterns of different-colored blotches that probably obscure the outlines of the lizard's body as it rests motionless on a rock or a tree trunk. ■Active foragers are usually slim and elongated with long tails, and they often have patterns of stripes that may produ ce optical illusions as they move. ■However, one predator-avoidance mechanism, the ability to break off their tailswhen they are seized by predators, does not differ among lizards with different foraging modes.■9. Look at the four squares that indicate where the following sentence could be added to the passage.Such visual effects make it harder for predators to catch these moving targets.Where would the sentence best fit? Click on a square to add the sentence to the passage.10. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selected THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points. Drag your choices to the spaces where they belong. To review the passage, click on View Text.Answer ChoicesO Sit-and-wait lizards use brief spurts of energy to forage, while the movements of active lizards are more sustained.O Lizards that are active foragers are able to detect insects even when those insects are stationary, but sit-and-wait lizards are able to detect only moving insects.O Sit-and-wait lizards tend to have predators that are active, while active lizards tend to have sit-and-wait predators.O Sit-and-wait lizards have less need for bodies that match their environment than active lizards do because of the ease with which they can break off their tails to escape from predators.O The body forms and metabolic functions of the two types of lizards differ in ways that support the requirements of their different foraging behaviors.O Sit-and-wait lizards derive energy for movement from anaerobic metabolism alone, while active lizards rely almost equally on aerobic and anaerobic metabolisms.。
新托福突破口TPO(1-30 纸质版)听力分类总结(用于横听及总结)
Art TPO1TPO3TPO3TPO7TPO8TPO9艺术Lecture1Lecture2Lecture3 Lecture1Lecture2Lecture1TPO16TPO17TPO18TPO19TPO22TPO24Lecture4Lecture1Lecture2Lecture4Lecture4Lecture2Anthropology TPO1TPO7TPO22人类学Lecture3Lecture3Lecture1Psychology TPO2TPO10TPO14TPO15TPO30心理学Lecture1Lecture4Lecture1Lecture1Lecture1Philosophy TPO2TPO28哲学Lecture3Lecture1Biology TPO1TPO2TPO4TPO6TPO7TPO8生物学Lecture4Lecture2Lecture1Lecture2Lecture2Lecture1TPO15TPO16TPO17TPO18TPO19TPO20Lecture4Lecture3Lecture4Lecture4Lecture3Lecture4TPO25TPO25TPO26纸质TPO4TPO27TPO27Lecture1Lecture4Lecture2Lecture2Lecture1Lecture3Astronomy TPO2TPO3TPO5TPO13TPO14TPO18天文学Lecture4Lecture4Lecture2Lecture4Lecture3Lecture1纸质TPO5TPO30Lecture3Lecture3Geology TPO1TPO4TPO6TPO7TPO9TPO15地质学Lecture2Lecture3Lecture4Lecture4Lecture3Lecture2Environmental TPO3TPO9TPO10TPO11TPO12TPO13环境科学Lecture1Lecture2Lecture3 Lecture3Lecture4Lecture2Business TPO6TPO11TPO12TPO26纸质TPO4商业Lecture1Lecture4Lecture2Lecture1Lecture1Chemistry TPO5TPO8化学Lecture3Lecture4Architecture TPO11TPO13TPO29建筑Lecture2Lecture1Lecture2History TPO8TPO10TPO17TPO18TPO21TPO25历史Lecture3Lecture2Lecture3 Lecture3 Lecture4Lecture2Archaeology TPO14TPO23TPO14TPO28TPO29考古学Lecture4Lecture1Lecture3 Lecture4Lecture3Linguistics TPO9TPO19TPO20语言学Lecture4Lecture1Lecture1Literature TPO4TPO5TPO6TPO20文学Lecture2Lecture4Lecture3 Lecture3杂类U.S. Governme TPO4Sociology TPO5Choreography T PO23美国政府Lecture4社会学Lecture1舞蹈Lecture4Structural Engine TPO29结构工程学Lecture4无老师题：很多筒子们在准备新托福考试的时候，都感觉一方面自己的能力确实是有问题，但是同太高，使得很多考生都应付不来，无老师这次幸得一份图片版新托福突破口TPO听力部分的分类总结，特地放出横听。
TPO 15 听力文本_Megan
TPO 15听力文本TPO 15 ScriptSection 1Conversation1Narrator:Listen to a conversation between a Student and the faculty Advisor of the campus newspaper.StudentHi! I talked to someone on the phone a couple of weeks ago, Anna, I think it was? AdvisorI'm Anna, the faculty advisor.StudentOh, great! I'm Peter Murphy. You probably don't r e member me, but …AdvisorNo! No! I remember you. You're interested in working for the paper.StudentYeah, as a reporter.AdvisorThat's right. You're taking a journ alism class and you’ve done some reporting before in high school, right?StudentWow, you have a good memory.AdvisorWell we haven’t had many s tudents applying lately so … so anyway, you still want to do some reporting for us?StudentYeah, if you have room for me on the staff.AdvisorWell we always need more reporters, but you know, we don't pay anything, right? StudentYeah, I know, but I huh.. . I'd like the experience. It would look good on my resume .AdvisorAbsolutely! Let's see. I think I told you that we ask prospective reporters to turn in some outlines for possible articles.StudentYeah, I sent them in about a week ago, but I haven't heard anything back yet, so, so I thought I'd stop by and see, but I guess you haven't looked at them yet.AdvisorOh, Max, the news editor. He looks a t all the submissions.StudentOh, so he hasn't made any decision about me yet?AdvisorWell I just got here a few minutes ago... haven't been in for a couple of days. Just give me a second to check my e-ma il. Uh … here is a message from Max. Let’s see. Well it seems you’ve really impressed him. He says it would be wonderful if you could join our staff. StudentOh, great! When can I start?AdvisorWell, you turned in an outline on something to do with the physics department? StudentYeah, they're trying to come up with ways to get more Students to take their introductory courses.AdvisorRight, well, apparently, nobody else is covering that story, so he wants you to follow up on it.StudentOK. Uh … wha t the other outline I sent in, about the proposed increase in tuition fees? AdvisorOh, it looks like we've got that coveredStudentSo I am starting with an article about the physics department. I guess I'd better get to work. Do you have any advice on how I should cover the story?AdvisorWell, Max will want to talk to you but I am sure he will tell you to find out things like why the physics department's worried about enrollment. Has the number of Students been getting smaller in recent years? By how much? What kinds of plans are they considering to address this problem?StudentRight, some of those issues are already in what I proposed.AdvisorAnd you'll want to do some interviews, you know, what do the Professors think of the plans, what do the Stu dents think you get the idea but …StudentBut wait till I talk to Max before proceeding.AdvisorRight, he'll cover everything you need to know to be a reporter for us. Can you come back this afternoon? He will be here until 5 o'clock.Lecture 1Narrator:Listen to part of a lecture in a psychology class.ProfessorFor decades, psychologists have been looking at our ability to perform tasks while other things are going on, how we are able to keep from being distracted and what the conditions for good concentration are. As long ago as 1982, researchers came up with something called the CFQ - the Cognitive Failures Questionnaire. This questionnaire asks people to rate themselves according to how often they get distracted in different situations, like hum … .. forgetti ng to save a computer file because they had something else on their mind or missing a speed limit sign on the road. John?JohnI've lost my share of computer files, but not because I’ m easily distracted. I just forget to save them.ProfessorAnd tha t's part of the problem with the CFQ. It doesn’t take other factors into account enough, like forgetfulness. Plus you really can’t say you are getting objective scientific results from a subjective questionnaire where people report on themselves. So it’s no surprise that someone attempted to design an objectiv e way to measure distraction. It’s a simple computer game designed by a psychologist named, Nilli Lavie. In Lavie’s game, people watch as the letters N and X appear and disappear in a certain area on the computer screen. Every time they see an N, they press one key, and every time they seean X they press another, except other letters also start appearing in the surrounding area of the screen with increasing frequency which creates a distraction and makes the task more diffic ult. Lav ie observed that people’s reaction time slowed as these distractions increased.StudentWell t hat’s not too surprising, isn’t it?ProfessorNo, it's not. It's the next part of the experiment that was surprising. When the difficulty really increased, when the screen filled up with letters, people got better at spotting the Xs and Ns. What (why) do you think that happened?JohnWell, maybe when we are really concentrating, we just don't perceive irrelevant information. Maybe we just don't take it in, you know?ProfessorYes, and that's one of the hypotheses that was proposed, that the brain simply doesn't admit the unimportant information. The second hypothesis is that, yes, we do perceive everything, but the brain categorizes the information, and whatever is not relevant to what we are concentrating on gets treated as low priority. So Lavie did another experiment, designed to look at the ability to concentrate better in the face of increased difficulty. This time she used brain scanning equipment to monitor activ ity in a certain part of the brain, the area called V5, which is part of the visual cortex, the part of our brains that processes visual stimuli.V5 is the area of the v isual cortex that's responsible for the sensation of movement. Once again, Lav ie gave people a computer-based task to do. They have to distinguish between words in upper and lower-case letters or even harder, they had to count the number of syllables in different words. This time the distraction was a moving star field in the background, you know, where H looks like you are moving through space, passing stars. Normally area of V5 would be stimulated as those moving stars are perceived and sure enough, Lavie found that during the task area of V5 was active, so people were aware of the moving star field. That means people were not blocking out the distraction. StudentSo doesn't that mean that the first hypothesis you mentioned was wrong, the one that says we don't even perceive irrelevant information when we are concentrating?ProfessorYes that's right, up to a point, bu t that’s not all. Lav ie also discovered that as she made the task more difficult, V5 became less active, so that means that now people wer en’t really noticing the star field at all. That was quite a surprise and it approved that the second hypothesis – that we do perceive everything all the time but the brain categorizesdistractions differently, well, that wasn't true either. Lavie thinks the solution lies in the brain’s ability to accept or ignore visual information. She th inks its capacity is limited. It’s like a highway. When there are too many cars, traffic is stopped. No one can get on. So when the brain is loaded to capacity, no new distractions can be perceived. Now that may be the correct conclusion for v isual distractions, but more research is needed to tell us how the brain deals with, say, the distractions of solv ing a math problem when we are hungry or when someone is singing in the next room.Lecture 2Narrator:Listen to part of a lecture in a geology class.ProfessorAs geologists, we examine layers of sediment on the Earth's surface to approximate the dates of past geologic time periods. Ah sediment as you know is material like sand , gravel, fossil fragments that is transported by natural processes like wind , water flow or the movement of glaciers . So sediment is transported and then deposited and it forms layers on the Earth’s surface over time. We examine these layers to learn about different geologic time periods including when they began and ended. For example, from about 1.8 million years ago to around 11 thousand years ago was the Pleistocene epic. The Pleistocene epic was an ice age. During this epic, sediment was made by the kind of erosion and weathering that happens when the climate is colder, and part of those sediments are fossils of plants and animals that lived at that time. The Holocene epic followed the Pleistoce ne epic when the Earth’s climate warmed up around 11 thousand years ago. The Holocene epic is characterized by different sediments, ones that form when the climate is warmer. Because the climate changed, the types of plants and animals changed also. Holocene sediments contain remnants of more recent plants and animals, so it's pretty easy to differentiate geologically between these two epics. Now there is growing evidence that the presence of humans has altered the earth so much that a new epic of geologic history has began(begun) – the Anthropocene epic, a new human-influenced epic. This idea that we’ve entered a new Anthro-pocene epic was first proposed in 2002. The idea is that around the year 1800 CE the human population became large enough, around a billion people, that its activities started altering the environment. This was also the time of the industrial revolution, which brought a tremendous increase in the use of fossil fuels such coal. The exploitation of fossil fuels has brought planet wide developments: industrialization, construction, uh, mass transport. And these developments have caused major changes like additional erosion of the Ear th’s surface and deforestation. Also, things like the damming of rivers, has caused increased sediment production, not to mention the addition of more carbon dioxide and methane in the atmosphere. Naturally all these changes show up in recent sediments. And these sediments are quite different from pre year 1800 sediment layers. Interestingly there's some speculation that humans started having a major impact on Earth much earlier, about 8000 years ago. That's when agriculture was becoming widespread. Early farmers started clearing forests and livestock produced a lot of extra methane. But I want to stress this is just a hypothesis. The ideathat early humans could have had such a major effect, well I'm just not sure we can compare it with the industrial age. Geologists in the far future will be able to examine the sediment being laid down today, whereas right now we can say that yes, human impact on the Earth is clear: It'll be future researchers who hav e a better perspective and will be able to really draw a line between the Holocene and the Anthropocene epics.Section 2Conversation2NarratorListen to part of a conversation between a Student and her biology.ProfessorHi Samantha, how did your track meet go?SamanthaGreat! I placed first in one race and third in another.ProfessorCongratulations! You must practice a lot.SamanthaThree times a week pre-season, but now that we’re competing every weekend, we practice 6 days a week from 3:30 till 5:00.ProfessorAthletics place a heavy demand on your time, don’t they?SamanthaYeah, but I really love competing, so …ProfessorYou know I played soccer in college and my biggest challenge, and I didn’t always succeed, was getting my studying in during soccer season. Are you having a similar …SamanthaNo, I … I really do make time to study. And I actually study more for this class than I do for all my other classes. But I didn’t see the grade I expected on my mid-term exam, which is why I came by.ProfessorWell, you "didn't do badly on the exam, but I agree it did not reflect your potential. I say this because your work on the lab project was exemplary. I was so impressed with the way you handle the microscope and the samples of onion cells, and with how carefully you observed and diagramed and interpreted each stage of cell division. And I don't think youcould have done that if you hadn't read and understood the chapter. I mean it seemed like you really had a good understanding of it.SamanthaI thought so too, but I missed some questions about cell division on the exam. ProfessorSo what happened?SamanthaI just sort of blanked out, I guess. I had a hard time remembering details. It was so frustrating.ProfessorAlright, let's back up. You say you studied, where, at home?SamanthaAt my kitchen table actually.ProfessorAnd that's supposed to be a quiet environment?SamanthaNot exactly. My brother and parents try to keep it down when I am studying, but the phone pretty much rings off the ho ok, so …ProfessorSo you might try a place with fewer distractions, like the library …SamanthaBut the library closes at mid-night, and I like to study all night before a test, you know, so everything is fresh in my mind. I studied six straight hours the night before the mid-term exam. That’s why I expected to do so much better.ProfessorOh ok. You know that studying six consecutive hours is not equivalent to studying one hour a day for six days.SamanthaIt isn’t?ProfessorNo. There is research that shows that after about an hour of intense focus, your brain needs a break. It needs to, you know, shift gears a little. Your brain's ability to absorb information starts to decline after about the first hour. So if you are dealing with a lot ofnew concepts and vocabulary, anyway, if you just reviewed your notes, even 20 minutes a day, it'd be much better than waiting until the night before an exam to try and absorb all those details .SamanthaOh, I didn't realize.ProfessorThink of your brain as: a muscle. If you didn't practice regularly with your track team, and then tried to squeeze in three weeks worth of running practice just the day before a track meet, how well do you think you'd perform in your races?Lecture 3Narrator:Listen to part of a lecture in an art history class.Professor:Now in Europe in the Middle Ages before the invention of printing and the printing press, all books, all manual scripts were hand-made. And the material typically used for the pages was parchment, which is animal skin that stretched and dried under tension, so it becomes really fat(flat) and can be written on . During the 1400s, when printing was being developed, paper became the predominant material for books in Europe, but prior to that, it was parchment. Parchment is durable, much more so than paper, and it could be reused which came in handy since it was a costly material and in short supply. So it wasn’t uncommon for the scribes or monks who produce the manual scripts. Ah, remember before printing books were made mainly in monasteries. Well, the scribes often recycled the parchment that’d been used for earlier manual scripts. They simply erased the ink off the parchment and wrote something new in its place A manual script page that was written on, erased and then used again is called a palimpsest. Palimpsests were created, well, we know about two methods that were used for removing ink from parchment. In the late Middle Ages, it was customary to scrape away the surface of the parchment with an abrasive, which completely wiped out any writing that was there. But earlier in the Middle ages, the original ink was usually removed by washing the used parchment with milk. That removed the ink. But with the passing of time, the original writing might reappear. In fact, it might reappear to the extent that scholars could make out an even decipher, the original text. Perhaps, the most famous example is the Archimedes' palimpsest. Archimedes lived in Greece around 200 BCE, and as you probably know, he's considered one of the greatest Mathematicians who ever lived, even though, many of his writings had been lost , including what many now think to be his most important work called The Method . But in 1998, a book of prayers from the Middle Ages sold in an art auction for a lot of money, more money than anyone would pay for a damaged book from the 12th century. Beautiful or not, why? It had been discovered that the book was a palimpsest, and beneath the surface writing on the manual script laid, guess what? Mathematical theorems and diagrams from Archimedes Archimedes' writings were originally done on papyrus scrolls. Then in the 10thcentury, a scribe made a copy on parchment of some of his texts and diagrams including, as it turns out, The Method. This was extremely fortunate, since later on, the original papyrus scrolls disappeared. About 200 years later in the 12th century, this parchment manual script became a palimpsest when a scribe used the parchment to make a prayer book. So the pages, the pieces of parchment themselves, had been preserved. But the Archimedes' text was erased and written over, and no one knew it existed. It wasn't until 1906 that a scholar came across the prayer book in a library and realized it was a palimpsest, and that the underlying layer of texts could only have come from Archimedes. That was when his work The Method was discovered for the first time. Um... the palimpsest then went through some more tough times, but eventually it ended up in an art auction where was bought and then donated to an art museum in Baltimore, for conservation and study. To avoid further damage to the manual script, the research team at the art museum has had to be extremely selective in their techniques they used to see the original writing. They've used ultraviolet light and some other techniques, and if you're interested in that sort of thing, you can learn more about it in an art conservation class. But actually, it was a physicist who came up with a method that was a breakthrough. He realized that the iron in the ancient ink would display if exposed to a certain X-ray imaging method, and except for small portions of the text that couldn't be deciphered, this technique's been very helpful in seeing Archimedes' texts and drawings through the medieval over writing.Lecture 4Narrator:Listen to part of a lecture in a biology class.Professor:OK. We've been talking till now about the two basic needs of a biological community – an energy source to produce organic materials, you know ah, food for the organism, and the waste recycling or breakdown of materials back into inorganic molecules, and about how all this requires photosynthesis when green plants or microbes convert sunlight into energy and also requires microorganisms, bacteria, to secrete chemicals that break down or recycle the organic material to complete the cycle So, now we are done with this chapter of the textbook, we can just review for the weekly quiz and move on to the next chapter, right? Well, not so fast. First, I’d like to talk about some discoveries that have challenged one of these fundamental assumptions about what you need in order to have a biological community. And, well, there actually were quite a few surprises. It all began in 1977 with the exploration of hydrothermal vents on the ocean floor. Hydrothermal vents are cracks in the Earth’s surface that occur, well, the ones we are talking about here are found deep at the bottom of the ocean. And these vents on the ocean floor, they release this incredibly hot water, 3-4 times the temperature that you boil water at because this water has been heated deep within the Earth. Well about 30 years ago, researchers sent a deep-sea vessel to explore the ocean ’ s depth, about 3 kilometers down, way deep to ocean floor, No one had ever explored that far down before. Nobody expected there to be any life down there because of the conditions. First of all, sunlight doesn't reach that far down so it’s totallydark. There couldn’t be any plant or animal life since there's no sunlight, no source of energy to make food. If there was any life at all, it’d just be some bacter ia breaking down any dead materials that might have fallen to the bottom of the ocean. And?StudentAnd what about the water pressure? Didn’t we talk before about how the deeper down into the ocean you go, the greater the pressure?ProfessorExcellent point! And not only the extreme pressure, but also the extreme temperature of the water around these vents. If the lack of sunlight didn't rule out the existence of a biological community down there then these factors certainly would, or so they thought. StudentSo you are telling us they did find organisms that could live under those conditions? Professor:They did indeed, something like 300 different speciesStudentBut... but how could that be? I mean without sunlight, no energy, no no …Professor:What they discovered was that microorganisms, bacteria, had taken over both functions of the biological community - the recycling of waste materials and the production of energy. They were the energy source. You see, it turns out that certain microorganisms are chemosynthetic - they don't need sunlight because they take their energy from chemical Reactions. So, as I said, unlike green plants which are photosynthetic and their energy from sunlight, these bacteria that they found at the ocean floor, these are chemosynthetic, which means that they get their energy from chemical reactions. How does this work? As we said, these hydrothermal vents are releasing into the ocean depth this intensely hot water and here is the thing, this hot water contains a chemical called hydrogen sulfide, and also a gas, carbon dioxide. Now these bacteria actually combine the hydrogen sulfide with the carbon dioxide and this chemical reaction is what produces organic material which is the food for larger organisms. The researchers had never seen anything like it before. StudentWow! So just add a chem ical to a gas, and bingo, you’ve got a food supply?ProfessorNot just that! What was even more surprising were all the large organisms that lived down there. The most distinctive of these was something called the tube worm. Here, let me show you a picture. The tube of the tube worm is really, really long. They can be up to oneand half meters long, and these tubes are attached to the ocean floor, pretty weird looking, huh? And another thing, the tube worm has no mouth, or digestive organs. So you are asking how does it eat? Well, they have these special organs that collect the hydrogen sulfide and carbon dioxide and then transfer it to another organ, where billions of bacteria live. These bacteria that live inside the tube worms, the tube worms provide them with hydrogen sulfide and carbon dioxide. And the bacteria, well the bacteria kind of feed the tube worms through chemosynthesis, remember, that chemical reaction I described earlier.。
【托福写作备考】TPO15综合写作文本与解析
【托福写作备考】TPO15综合写作文本与解析TPO 15先来看看以下阅读材料：The cane toad is a large (1.8 kg) amphibian species native to Central and South America. It was deliberately introduced to Australia in 1935 with the expectation that it would protect farmers’ crops by eating harmful insects. Unfortunately, the toad multiplied rapidly, and a large cane toad population now threatens small native animals that are not pest. Several measures have been proposed to stop the spread of the cane toad in Australia.中文：蔗蜍是一种原产于中南美洲的两栖动物，个头很大，重大1.8公斤。
蔗蜍是在1935年由人工引进至澳大利亚的。
因为它们可以吃害虫，所以希望借由它们保护农作物。
不幸的是，蔗蜍繁殖迅速。
而且，数量巨大的蔗蜍群体已经开始威胁一些对农业无害的小型本土生物。
现在提出了几个解决蔗蜍在澳大利亚蔓延的方法。
One way to prevent the spread of the toad would be to build a national fence.A fence that blocks the advance of the toads will prevent them from moving into those parts of Australia that they have not yet colonized. This approach has been used before: a national fence was erected in the early part of the twentieth century to prevent the spread of rabbits, another animal species that was introduced in Australia from abroad and had a harmful impact on its native ecosystems.中文：第一个阻止蔗蜍蔓延的方法是建立一个全国范围的围栏。
托福TPO15口语Task3阅读文本+听力文本+题目+满分范文
为了帮助大家高效备考托福，为大家带来托福TPO15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TPO15口语Task3阅读文本： University Should Pave Running Trails The university has about three miles of unpaved dirt running trails that pass through the forest near campus. I think these trails should be paved with cement. One reason for paving the trails would be to increase their safety. When it rains, the dirt turns to mud and becomes very slippery, so the runners who use them can slip and fall. Pavement would solve this problem. Also, paving would make the trails look nicer, which would encourage students to use them. Bumps in the trail would be smoothed out and weeds would be paved over, making the trail more attractive to runners. Sincerely, Sally Jacobs 托福TPO15口语Task3听力文本： Now listen to two students discussing the letter. (woman) Hey, Ted, you're a runner. Did you see this letter in the paper? (man) Yeah, I did, and I use those. (woman) And? (man) I think it's a terrible idea. (woman) How come? (man) Well, she really hasn't thought it through. Like, the thing about making them safer, what's she's not thinking about is the long-term consequence of running on a hard surface. (woman) What do you mean? (man) I mean, it's not good for you. It's too hard on your bones and joints. If you run repeatedly on hard surface, it can lead to injuries or, that's what I've been taught anyway, it's better to run on a soft surface. It does less damage to your body. (woman) Oh, I wasn't aware of that. (man) Yeah, so actually it wouldn't be safer. And her second point… (woman) About changing the way they look? (man) Yeah, I don't think people will like it. (woman) So they'd use them less? (man) Yeah, I mean, one of the main reasons people enjoy them now was it’s a way of taking a break from the rest of the campus, from buildings and streets and stuff. It’s, you know, a chance that feels like you’re out in the nature. (woman) Oh, so you wouldn't bet that effect anymore. (man) Right! It’d be just like you’re on a regular street or sidewalk. It wouldn't be as relaxing. 托福TPO15口语Task3题目： The man expresses his opinion about the proposal in the student’s letter. Briefly summarize the proposal. Then state the man’s opinion about the proposal and explain the reasons he gives for holding that opinion. 托福TPO15口语Task3满分范文： Well, the proposal says that the university should pave the dirt trail with cement for two reasons. However the man doesn't agree with the proposal for some reasons. First of all, he argues that it's safer for people to run repeatedly on a trail with soft surface than on a paved one, simply because it'll do less damage and injuries to human bodies. Besides, he is against the proposal's second opinion mainly because students will take a break for walking on the trail, since it's more natural and students would have a chance to relax. So based on the reasons above the man disagrees with the proposal. (106 words) 以上是给大家整理的托福TPO15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!。
托福TPO15口语Task4阅读文本+听力文本+题目+满分范文
为了帮助大家高效备考托福，为大家带来托福TPO15口语Task4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TPO15口语Task4阅读文本： Experimenter Effect One objective of any experiment is, of course, to obtain accurate results.Sometimes, however, problems occur that lead to in accurate results. One such problem is the experimenter effect. The experimenter effect occurs when searcher ’s expectations affect the outcome of the experiment. The researcher expects a particular result from the experiment, and that expectation causes the researcher to act in ways that influence the behavior of the experiment participants, thereby invalidating the results of the experiment. 托福TPO15口语Task4听力文本： (male professor) For example, I recently read about a case in which a researcher was given two groups of monkeys and he was asked to train these monkeys to pick up a ball and put it in a box, and he was told to record how many hours it took to train each monkey to learn to do this.Now, before he started the training, the researcher was told that one group of monkeys was highly intelligent and the other group was less intelligent. In truth, there was no difference between them. All the monkeys were actually very similar in terms of intelligence. But the researcher didn't know that. He thought one group was smarter, so he expected that group would be easier to train.So, what happened? Well, the researcher trained the monkeys to perform the action, and it turned out that, on average, it took him two hours less time to train the supposedly smart monkeys than the supposedly less intelligent monkeys. Why? Well, it turns out that with the supposedly smart monkeys the researcher smiled at them a lot, gave them a lot of encouragement, talked to them a lot, worked hard to communicate with them. But with the monkeys he thought were less intelligent, he wasn’t this enthusiastic, he didn’t try this hard, wasn’t quite optimistic. 托福TPO15口语Task4题目： Explain how the example from the professor’s lecture illustrates the experimenter effect. 托福TPO15口语Task4满分范文： When the researchers expect certain result during their experiment, the expectations usually affect the outcome. This phenomenon is called experimentereffect. The professor illustrates this with a monkey experiment that he read about. In the experiment, a researcher was given two groups of monkey and asked to teach them to pick up a ball and put it in a box. And he had been told that one group was smarter than the other, which was not true. Therefore, anyway, the researcher expected that the smarter group was easier to train. And it took two hours less time to train the supposedly smarter monkey because he tried to communicate with them, frequently smiled at them, encouraged them, and talked to them. While with the other group, he was not that enthusiastic. So actually it's the researcher's behavior that influenced the result. That's how experimenter effect is achieved during the experiment. (152 words) 以上是给大家整理的托福TPO15口语Task4阅读文本+听力文本+题目+满分范文，希望对你有所帮助!。
听力c15t2s3解析
听力c15t2s3解析Task: Listening C15T2S3 AnalysisIn this task, I will provide a detailed analysis of Listening C15T2S3 from an academic perspective. This listening section is part of Practice Test 2 in Cambridge IELTS 15.Listening C15T2S3 focuses on a conversation between a student named Sarah and her tutor, discussing her research project for a history course. The conversation revolves around the topic of changing perceptions of women's roles during the Industrial Revolution.The dialogue begins with Sarah explaining her research topic, which focuses on exploring women's experiences during the Industrial Revolution. She mentions that she wants to examine the lives of working-class women and their contribution to society. Sarah also expresses her fascination with the changes brought about by industrialization and how they impacted women's roles.Sarah and her tutor then discuss potential sources for her research, including autobiographies, diaries, newspaper articles, and other primary sources. The tutor emphasizes the importance of using reliable and credible sources for historical research.Furthermore, the tutor suggests Sarah consider the influence of economic factors on women's roles, such as the growth of factories and the increasing demand for female labor. They also discuss the impact of technological advancements on women's work and the social changes that occurred as a result.Throughout the conversation, the tutor provides guidance and advice to Sarah, encouraging her to critically analyze the sources she finds. They discuss the potential biases of different authors and the importance of cross-referencing multiple sources to form a well-rounded understanding of the topic.The listening section concludes with the tutor advising Sarah on how to structure her research project. They discuss the significance of a clear thesis statement, organizing the research into coherent sections, and presenting a balanced argument. The tutor also suggests incorporating visuals, such as graphs or charts, to support her findings.In summary, Listening C15T2S3 provides insight into the research process and the importance of exploring different perspectives when studying historical topics. Through the conversation between Sarah and her tutor, listeners gain a better understanding of the challenges and considerations involved in conducting an academic research project.(Note: This analysis is a hypothetical response to the given task description and does not represent a real article or transcript.)。
托福阅读真题第151篇TwoKindsofLizards
托福阅读真题第151篇TwoKindsofLizards第1段：蜥蜴按觅食方式可分为两种：静坐觅食型和主动型觅食型。
坐等蜥蜴通常呆在一个可以调查广阔区域的地方。
这些一动不动的蜥蜴目测昆虫的运动，并从观察点快速跑动捕捉它。
坐等蜥蜴可能最成功地检测和捕获相对较大的昆虫，如甲虫和鹅肝店员。
另一方面，活跃的觅食者大部分时间都在地面上度过，稳定地移动并将头从落叶下探入地下的裂缝中。
这些蜥蜴显然主要依靠化学线索来检测昆虫，它们可能会寻找局部集中的猎物，例如白蚁。
活跃的觅食者似乎比坐等捕食者的蜥蜴吃更多的昆虫。
因此，蜥蜴的不同觅食行为导致它们的饮食不同，即使两种蜥蜴出现在同一栖息地。
1. 根据第1 段，坐等式觅食者和主动式觅食者在以下所有方面都不同，除了O 他们主要用来检测昆虫的方法O 他们通常吃的昆虫数量O 可以找到它们的栖息地O 他们移动所花费的时间2. 根据第1 段，与坐等蜥蜴通常食用的昆虫相比，活动蜥蜴通常食用的昆虫O 移动得更快O 通常出现在较小的群体中O经常隐藏在视线之外O 花更多时间在地面上第2 段：不同的觅食方式对蜥蜴在暴露于捕食者方面也有不同的影响。
99% 的时间都在静止不动的蜥蜴相对不显眼，而大部分时间都在移动的蜥蜴很容易被看到。
坐等蜥蜴可能最有可能被活跃的捕食者发现和捕获，而广泛觅食的蜥蜴很可能被坐等捕食者捕获。
由于这种差异，觅食模式可能在食物链中的连续水平上交替：四处走动的昆虫可能会被坐等觅食的蜥蜴捕获，而这些蜥蜴可能会被活跃的捕食者吃掉，而久坐不动的昆虫可能会吃掉它们。
更有可能被活跃的觅食蜥蜴发现，3.在第2段中，为什么作者将大部分时间静止不动的蜥蜴的可见性与大部分时间移动的蜥蜴的可见性进行对比？O 表明蜥蜴有可能在食物链的连续水平上交替觅食模式O 建议坐等蜥蜴比活跃的蜥蜴更容易受到捕食者的攻击O 解释为什么坐等蜥蜴在捕食昆虫方面比活跃的蜥蜴更成功O 解释蜥蜴的觅食策略如何影响可能攻击它的捕食者类型第3 段：静坐觅食者的身体形态可能反映了与活跃觅食者不同的选择压力。
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【托福听力资料】托福TPO15 听力文本-Lecture 4众所周知，托福TPO材料是备考托福听力最好的材料。
相信众多备考托福的同学也一直在练习这套材料，那么在以下内容中我们就为大家带来托福TPO听力练习的文本，希望能为大家的备考带来帮助。
TPO 15 Lecture 4 BiologyNarrator: Listen to part of a lecture in a biology class.Professor:OK. We’ve been talking till now about the two basic needs of a biologicalcommunity – an energy source to produce organic materials, you know uh, food forthe organisms, and the waste recycling or breakdown of materials back intoinorganic molecules, and about how all this requires photosynthesis when greenplants or microbes convert sunlight into energy, and also requiresmicroorganisms, bacteria, to secrete chemicals that break down or recycle theorganic material to complete the cycle. So, now we are done with this chapter ofthe textbook, we can just review for the weekly quiz and move on to the nextchapter, right? Well, not so fast. First, I ‘d like to talk about somediscoveries that have challenged one of these fundamental assumptions about whatyou need in order to have a biological community.And, well, there actually were quite a few surprises. It all began in 1977with the exploration of hydrothermal vents on the ocean floor. Hydrothermalvents are cracks in the Earth’s surface that occur, well, the ones we aretaiking about here are found deep at the bottom of the ocean. And these vents onthe ocean floor, they release this incredibly hot water, 3 to 4 times the temperature that you boil water at, because this water has been heated deep within the Earth.Well about 30 years ago, researchers sent a deep-sea vessel to explore the ocean’s depth, about 3 kilometers down, way deep to the ocean floor, No one had ever explored that far down before. Nobody expected there to be any life down there because of the conditions.First of all, sunlight doesn’t reach that far down so it ’ s totally dark. There couldn’t be any plant or animal life since there’s no sunlight, no source of energy to make food. If there was any life at all, it’d just be some bacteria breaking down any dead materials that might have fallen to the bottom of the ocean . And?Student 1 ：And what about the water pressure? Didn ’ t we talk before about how the deeper down into the ocean you go, the greater the pressure? Professor ：Excellent point! And not only the extreme pressure, but also the extreme temperature of the water around these vents. If the lack of sunlight didn’t rule out the existence of a biological community down there then these factors certainly would, or so they thought.Student 2：So you are telling us they did find organisms that could live under those conditions?Professor: They did indeed, something like 300 different species.Student 1 ：But... but how could that be? I mean without sunlight, no energy,no no …Protessor:What they discovered was that microorganisms, bacteria, had taken over both functions of the biological community - the recycling of waste materials and the production of energy. They were the energy source. You see, it turns out that certain microorganisms are chemosynthetic - they don’t need sunlight because they take their energy from chemical reactions.So, as I said, unlike green plants which are photosynthetic and get their energy from sunlight, these bacteria that they found at the ocean floor, these are chemosynthetic, which means that they get their energy from chemical reactions. How does this work?As we said, these hydrothermal vents are releasing into the ocean depth this intensely hot water and here is the thing, this hot water contains a chemical called hydrogen sulfide, and also a gas , carbon dioxide. Now these bacteria actually combine the hydrogen sulfide with the carbon dioxide and this chemical reaction is what produces organic material which is the food for larger organisms. The researchers had never seen anything like it before.Student 2 : Wow! So just add a chemical to a gas, and bingo, you ’ ve got a food supply?ProfessorNot just that! W hat was even more surprising were all the large organisms that lived down there. The most distinctive of these was something called thetube worm. Here, let me show you a picture . The tube of the tube worm is really, really long. They can be up to one and a half meters long , and these tubes are attached to the ocean floor, pretty weird looking, huh?And another thing, the tube worm has no mouth or digestive organs. So you are asking how does it eat? Well, they have these special organs that collect the hydrogen sulfide and carbon dioxide and then transfer it to another organ, where billions of bacteria live. These bacteria that live inside the tube worms, the tube worms provide them with hydrogen sulfide and carbon dioxide. And the bacteria, well the bacteria kind of feed the tube worms through chemosynthesis, remember, that chemical reaction I described earlier.。