托福阅读tpo42-1WORD打印 Explaining Dinosaur Extinction
Explaining Dinosaur ExtinctionDinosaurs rapidly became extinct about 65 million years ago as part of a mass extinction known as the K–T event, because it is associated with a geological signature known as the K–T boundary, usually a thin band of sedimentation found in various parts of the world (K is the traditional abbreviation for the Cretaceous, derived from the German name Kreidezeit). []Many explanations have been proposed for why dinosaurs became extinct.[] For example, some have blamed dinosaur extinction on the development of flowering plants, which were supposedly more difficult to digest and could have caused constipation or indigestion-except that flowering plants first evolved in the Early Cretaceous, about 60 million years before the dinosaurs died out.[] In fact, several scientists have suggested that the duckbill dinosaurs and horned dinosaurs, with their complex battery of grinding teeth, evolved to exploit this new resource of rapidly growing flowering plants.[] Others have blamed extinction on competition from the mammals, which allegedly ate all the dinosaur eggs-except that mammals and dinosaurs appeared at the same time in the Late Triassic, about 190 million years ago, and there is no reason to believe that mammals suddenly acquired a taste for dinosaur eggs after 120 million years of coexistence. Some explanations (such as the one stating that dinosaurs all died of diseases) fail because there is no way to scientifically test them, and they cannot move beyond the realm of speculation and guesswork.In paragraph 1, why does the author include a discussion of when flowering plants evolved?∙To help explain why some scientists believe that the development of flowering plants led to dinosaur extinction∙To cast doubt on the theory that the development of flowering plants caused dinosaurs to become extinct∙To suggest that dinosaurs were able to survive for as long as they did because of the availability of flowering plants∙To emphasize that duckbill dinosaurs and horned dinosaurs were the first dinosaurs to become extinctThe word "allegedly" in the passage is closest in meaning to∙inevitably∙gradually∙supposedly∙increasinglyAccording to paragraph 1, the extinction of the dinosaurs is unlikely to have been the result of competition from mammals because∙mammals would not have been capable of eating dinosaur eggs∙mammals did not appear in any significant numbers until after the Late Triassic∙mammals and dinosaurs did not, in fact, compete for any of the same resources∙mammals and dinosaurs lived together for roughly 120 million years before the extinction This focus on explaining dinosaur extinction misses an important point: the extinction at the end of the Cretaceous was a global event that killed off organisms up and down the food chain. It wiped out many kinds of plankton in the ocean and many marine organisms that lived on the plankton at the base of the food chain. These included a variety of clams and snails, and especially the ammonites, a group of shelled squidlike creatures that dominated the Mesozoic seas and had survived many previous mass extinctions. The K–T event marked the end of the marine reptiles, such as the mosasaurs and the plesiosaurs, which were the largest creatures that had ever lived in the seas and which ruled the seas long before whales evolved. On land, there was also a crisis among the land plants, in addition to the disappearance of dinosaurs. So any event that can explain the destruction of the base of the food chain (plankton in the ocean, plants on land) can better explain what happened to organisms at the top of the food chain, such as the dinosaurs. By contrast, any explanation that focuses strictly on the dinosaurs completely misses the point. The Cretaceous extinctions were a global phenomenon, and dinosaurs were just a part of a bigger picture.According to paragraph 2, what is problematic about some scientists' focus on dinosaur extinction?∙Dinosaurs became extinct so long ago that no theory about their disappearance can be proven scientifically.∙Dinosaurs were not the only organisms that went extinct at the end of the Cretaceous period.∙More marine organisms went extinct during the Cretaceous than did dinosaur species.∙It is more important to understand how plankton and other marine organisms came to thrive during the Cretaceous period.According to paragraph 2, each of the following became extinct during the K–T event EXCEPT∙early species of whales∙marine reptiles∙various species of clams∙many species of land plantsWhat makes the extinction of "the ammonites" especially significant?∙They were among the largest creatures that ever lived.∙They existed at the lowest level of the food chain.∙They had been able to survive in the Mesozoic seas.∙They had survived many previous mass extinctions.According to one theory, the Age of Dinosaurs ended suddenly 65 million years ago when a giant rock from space plummeted to Earth. Estimated to be ten to fifteen kilometers in diameter, this bolide (either a comet or an asteroid) was traveling at cosmic speeds of 20–70 kilometers per second, or 45,000–156,000 miles per hour. Such a huge mass traveling at such tremendous speeds carries an enormous amount of energy. When the bolide struck, this energy was released and generated a huge shock wave that leveled everything for thousands of kilometers around the impact and caused most of the landscape to burst into flames. The bolide struck an area of the Yucatán Peninsula of Mexico known as Chicxulub, excavating a crater 15–20 kilometers deep and at least 170 kilometers in diameter. The impact displaced huge volumes of seawater, causing much flood damage in the Caribbean. Meanwhile, the bolide itself excavated 100 cubic kilometers of rock and debris from the site, which rose to an altitude of 100 kilometers. Most of it fell back immediately, but some of it remained as dust in the atmosphere for months. This material, along with the smoke from the fires, shrouded Earth, creating a form of nuclear winter. According to computerized climate models, global temperatures fell to near the freezing point, photosynthesis halted, and most plants on land and in the sea died. With the bottom of the food chain destroyed, dinosaurs could not survive.How does paragraph 3 relate to paragraph 2?∙Paragraph 3 provides an alternative explanation to the one provided in paragraph 2.∙Paragraph 3 provides an explanation that satisfies the conditions set forth in paragraph 2.∙Paragraph 3 provides the facts to support the theory presented in paragraph 2.∙Paragraph 3 presents a theory that calls into question the position described in paragraph2.Paragraph 3 strongly suggests that if the bolide impact theory is correct, the majority of the extinctions associated with the K–T event resulted from∙sunlight being blocked for months by dust and smoke in Earth's atmosphere∙widespread flooding that followed the displacement of huge volumes of seawater∙the leveling of the landscape by the shock wave that was generated when the bolide struck Earth∙the rise in global temperatures caused by the fires that burned much of the landscapeLook at the four squares [] that indicate where the following sentence could be added to the passage.Some explanations seem plausible until the facts are considered.Drag your answer choices to the spaces where they belong. To remove an answer choice, click on it.To review the passage, click VIEW TEXT.Over the years, scientists have proposed a number of theories as to why dinosaurs suddenly became extinct about 65 million years ago.∙∙∙Answer ChoicesA. Many explanations for dinosaur extinction have been proposed, but most ofthem are either called into question by known facts or are merely unsupported hypotheses.B. Although mammals and dinosaurs appeared at about the same time in theLate Triassic, the K–T event, which marked the end of the dinosaurs, apparently had relatively little impact on mammals.C.Focusing on dinosaurs misses the point that the extinction, at about thesame time, of the shelled squidlike creatures that dominated the Mesozoic seas was far more scientifically significant.D. Any satisfactory explanation of the mass extinction of dinosaurs must takeinto account the fact that the disappearance of the dinosaurs was part of a global mass extinction.puterized climate models of global temperature fluctuations supportthe theory that a huge rock from space hit the Yucatan Peninsula in Mexico about 65 million years ago.F. A huge bolide striking Earth would have created conditions in which mostplants would have died, thus explaining the mass extinction of organisms—including dinosaurs—further up the food chain.。
托福TPO4综合写作阅读原文+听力原文+满分范文
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托福TPO4综合写作阅读原文文本： Endotherms are animals such as modern birds and mammals that keep their body temperatures constant. For instance, humans are endotherms and maintain an internal temperature of 37°C, no matter whether the environment is warm or cold. Because dinosaurs were reptiles, and modern reptiles are not endotherms, it was long assumed that dinosaurs were not endotherms. However, dinosaurs differ in many ways from modem reptiles, and there is now considerable evidence that dinosaurs were, in fact, endotherms. Polar dinosaurs One reason for believing that dinosaurs were endotherms is that dinosaur fossils have been discovered in polar regions. Only animals that can maintain a temperature well above that of the surrounding environment could be active in such cold climates. Leg position and movement There is a connection between endothermy and the position and movement of the legs. The physiology of endothermy allows sustained physical activity, such as running. But running is efficient only if an animal's legs are positioned underneath its body, not at the body's side, as they are for crocodiles and many lizards. The legs of all modern endotherms are underneath the body, and so were the legs of dinosaurs. This strongly suggests that dinosaurs were endotherms. Haversian canals There is also a connection between endothermy and bone structure. The bones of endotherms usually include structures called Haversian canals. These canals house nerves and blood vessels that allow the living animal to grow quickly, and rapid body growth is in fact a characteristic of endothermy. The presence of Haversian canals in bone is a strong indicator that the animal is an endotherm, and fossilized bones of dinosaurs are usually dense with Haversian canals. 托福TPO4综合写作听力原文文本： Many scientists have problems with the arguments you read in the passage. They don't think those arguments prove that dinosaurs were endotherms. Take the polar dinosaur argument. When dinosaurs lived, even the polar regions, where dinosaur fossils have been found, were much warmer than today, warm enoughduring part of the year for animals that were not endotherms to live. And during the months when the polar regions were cold, the so-called polar dinosaurs could have migrated to warmer areas or hibernated like many modern reptiles do. So the presence of dinosaur fossils in polar regions doesn't prove the dinosaurs were endotherms. Well, what about the fact that dinosaurs have their legs placed under their bodies, not out to the side like crocodiles. That doesn't necessarily mean dinosaurs were high-energy endotherms built for running. There is another explanation for having legs under the body. This body structure supports more weight, so with the legs under their bodies, dinosaurs can grow to a very large size. Being large had advantages for dinosaurs, so we don't need the idea of endothermy and running to explain why dinosaurs evolved to have their legs under their bodies. Ok, so how about bone structure? Many dinosaur bones do have Haversian canals, that's true. The dinosaur bones also have growth rings. Growth rings are thickening of the bone that indicates periods of time when the dinosaurs weren't rapidly growing. These growth rings are evidence that dinosaurs stopped growing or grew more slowly during cooler periods. This pattern of periodic growth, you know, rapid growth followed by no growth or slow growth, and then rapid growth again, is characteristic of animals that are not endotherms. Animals that maintain a constant body temperature year-round as true endotherms do grow rapidly even when the environment becomes cool. 托福TPO4综合写作满分范文： The professor actually contradicts the statements made in the passage. She is of the view that dinosaurs are not endotherms i.e. they were not able to keep their body temperature at a constant rate. The professor contradicts the issue of dinosaurs being endothers based on the availability of fossils being available in the polar regions, she say that the polar regions in those days were not as cold as they are today i.e at least warm enough for dinosaurs to live. Durin harsh winters she says that there is a possibility of the dinosaurs actually migrating to warmer regions. The issue of leg position and movement being used as a reason to clasify the dinosaurs as endotherms does not please the professor either. She says that dinosaurs had legs under their bodies to support their huge bodies i.e the legs under the body of the dinosaur were actually to support the huge weight of the dinosaur and not to provide it with a body structure like endotherms(which is actually suited for running). The professor acknowledges the presence of haversian canals but also points out that that the fossils show the presence of growth rings. These rings occur due to the thickening of the bone. The thickening indicates that the dinosaurs were’nt。
托福口语｜TPO42题目+文本
小编给考生们带来了托福TPO42口语文本，希望大家多做题，多积累、多研究，有针对性的规划考试。
托福TPO42口语task1题目:Choose an accomplishment that required you to work very hard. Explain whatthe accomplishment was and why it was important to you.托福TPO42口语task2题目:Some people prefer living in a big city. Other people prefer living in thecountryside, away from urban areas. Which do you think is better? Explain whyusing specific details in your explanation.托福口语TPO42 Task3(听力+阅读+题目):No More Evening ClassesReading Part:No More Evening ClassesThe administration has announced that starting next fall, the universitywill stop offering evening classes in many departments. According to auniversity administrator, the decision was prompted by a steady decline inenrollments in evening classes. Evening classes are just too small, theadministrator said. When asked to explain the decline in enrollments, theadministrator pointed to the fact that most evening classes are taught byteaching assistants, who are usually graduate students. Surveys show thatstudents prefer to take classes taught by experienced faculty members, thespokesperson said, " Probably because they simply know more than graduateteaching assistants do.Question:The man disagrees with the decision announced in the student newspaper.Explain why the university made the decision and why the man disagrees with.托福口语TPO42 Task4(阅读+题目):HabituationReading Part:HabituationHabituation is a form of learning that is quite common among animals. Whenan animal experiences a situation for the first time, particularly one it considers threatening, it may instinctively respond by running away or by warning other members of its community with alarm calls. Normally, it responds this way each time the situation occurs. However, if through continuous and prolonged exposure the animal learns that the situation is harmless the behavior gradually diminishes. Ultimately, it will stop responding to the situation altogether. Thus, through habituation a natural or instinctive behavior gradually changes.Question:The man disagrees with the decision announced in the student newspaper. Explain why the university made the decision and why the man disagrees with.托福口语TPO42 Task5:Possible SolutionsQuestion:The speakers discuss two possible solutions to the woman’s problem. Briefly summarize the problem. Then state which solution you recommend and why.托福口语TPO42 Task6:Climate ChangeQuestion:Using the example of the thunder bird, explain apossible effect of a major climate change.。
TPO 42 Reading 1 解析
Passage 1Q 1正确答案：B解析：这句话的意思是，从基因池分离是很多物种形成的重大事件。
这里的“key”意为“至关重要的”，与crucial的意思相符。
其余选项意义分别是“早期的”、“可察觉的”和“经常性的”，均不能体现“重要”的含义，故排除。
Q 2正确答案：C解析：这句话的意思是，最初的隔离往往是地理屏障造成的。
这里的“initial”意思是“最初的”，与first的意思相符。
其余选项分别意为“最好的”、“一般的”和“真实的”，故排除。
Q 3正确答案：B解析：第1段最后一句句首的this mode of evolving new species指的是前一句的内容In the formation of many species, the initial isolation of a population seems to have been a geographic barrier.选项B是对这句话的同义转述。
Q 4正确答案：A解析：第1段介绍了地理屏障对物种形成的影响，第2段介绍了地理屏障对物种形成影响的一些具体例子，如山脉和冰川，可见，第2段是对第1段的进一步说明。
B错在discoveries，C中的gene pool becomes isolated是对原文内容的过度理解。
第2段并不是为了解释allopatric 这个术语，故D错误。
Q 5正确答案：D解析：第3段是总——分结构，前两句指出，地理屏障对于生物物种隔离的影响取决于生物跨越这些屏障的能力，后面几句话则列举了一些能够跨越屏障和不能跨越屏障的一些例子进行了说明。
D是对本段第2句的同义转述。
本段并未涉及动物和植物跨越障碍的比较，故A 错误。
B是对第5句的曲解。
C是对原文中列举的antelope squirrel这个物种的曲解。
Q 6正确答案：C解析：第3段第5句指出，In contrast, small rodents may find a deep canyon or a wide river an effective barrier.接下来列举了两种antelope squirrels的例子进行了说明。
托福TPO42阅读Passage2原文文本+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TPO42阅读Passage2原文文本+题目+答案解析，希望对大家备考有所帮助。
Explaining Dinosaur Extinction Dinosaurs rapidly became extinct about 65 million years ago as part of a mass extinction known as the K-T event,because it is associated with a geological signature known as the K-T boundary,usually a thin band of sedimentation found in various parts of the world(K is the traditional abbreviation for the Cretaceous,derived from the German name Kreidezeit).Many explanations have been proposed for why dinosaurs became extinct.For example,some have blamed dinosaur extinction on the development of flowering plants,which were supposedly more difficult to digest and could have caused constipation or indigestion—except that flowering plants first evolved in the Early Cretaceous,about 60 million years before the dinosaurs died out.In fact,several scientists have suggested that the duckbill dinosaurs and homed dinosaurs,with their complex battery of grinding teeth,evolved to exploit this new resource of rapidly growing flowering plants Others have blamed extinction on competition from the mammals,which allegedly ate all the dinosaur eggs—except that mammals and dinosaurs appeared at the same time in the Late Triassic,about 190 million years ago,and there is no reason to believe that mammals suddenly acquired a taste for dinosaur eggs after 120 million years of coexistence Some explanations(such as the one stating that dinosaurs all died of diseases)fail because there is no way to scientifically test them,and they cannot move beyond the realm of speculation and guesswork. This focus on explaining dinosaur extinction misses an important point the extinction at the end of the Cretaceous was a global event that killed off organisms up and down the food chain.It wiped out many kinds of plankton in the ocean and many marine organisms that lived on the plankton at the base of the food chain.These included a variety of clams and snails,and especially the ammonites,a group of shelled squidlike creatures that dominated the Mesozoic seas and had survived many previous mass extinctions.The K-T event marked the end of the marine reptiles,such as the mosasaurs and the plesiosaurs,which were the largest creatures that had ever lived in the seas and which ruled the seas long before whales evolved.On land,there was also a crisis among the land plants,in addition to the disappearance of dinosaurs.So any event that can explain the destruction of the base of the food chain(plankton in the ocean,plants on land)can better explain what happened to organisms at the top of the food chain,such as the dinosaurs.By contrast,any explanation that focuses strictly on the dinosaurs completely misses the point The Cretaceous extinctions were a global phenomenon,and dinosaurs were just a part of a bigger picture. According to one theory,the Age of Dinosaurs ended suddenly 65 million years ago when a giant rock from space plummeted to Earth.Estimated to be ten to fifteen kilometers in diameter,this bolide(either a comet or an asteroid)was traveling at cosmic speeds of 20-70 kilometers per second,or 45,000-156,000 miles per hour.Sucha huge mass traveling at such tremendous speeds carries an enormous amount of energy.When the bolide struck this energy was released and generated a huge shock wave that leveled everything for thousands of kilometers around the impact and caused most of the landscape to burst into flames.The bolide struck an area of the Yucatan Peninsula of Mexico known as Chicxulub,excavating a crater 15-20 kilometers deep and at least 170 kilometers in diameter.The impact displaced huge volumes of seawater,causing much flood damage in the Caribbean.Meanwhile,the bolide itself excavated 100 cubic kilometers of rock and debris from the site,which rose to an altitude of 100 kilometers.Most of it fell back immediately,but some of it remained as dust in the atmosphere for months.This material,along with the smoke from the fires,shrouded Earth,creating a form of nuclear winter.According to computerized climate models,global temperatures fell to near the freezing point,photosynthesis halted,and most plants on land and in the sea died.With the bottom of the food chain destroyed,dinosaurs could not survive. paragraph 1 Dinosaurs rapidly became extinct about 65 million years ago as part of a mass extinction known as the K-T event,because it is associated with a geological signature known as the K-T boundary,usually a thin band of sedimentation found in various parts of the world(K is the traditional abbreviation for the Cretaceous,derived from the German name Kreidezeit).Many explanations have been proposed for why dinosaurs became extinct.For example,some have blamed dinosaur extinction on the development of flowering plants,which were supposedly more difficult to digest and could have caused constipation or indigestion—except that flowering plants first evolved in the Early Cretaceous,about 60 million years before the dinosaurs died out.In fact,several scientists have suggested that the duckbill dinosaurs and homed dinosaurs,with their complex battery of grinding teeth,evolved to exploit this new resource of rapidly growing flowering plants Others have blamed extinction on competition from the mammals,which allegedly ate all the dinosaur eggs—except that mammals and dinosaurs appeared at the same time in the Late Triassic,about 190 million years ago,and there is no reason to believe that mammals suddenly acquired a taste for dinosaur eggs after 120 million years of coexistence Some explanations(such as the one stating that dinosaurs all died of diseases)fail because there is no way to scientifically test them,and they cannot move beyond the realm of speculation and guesswork. 1.In paragraph 1,why does the author include a discussion of when flowering plants evolved? 【事实信息题】 A.To help explain why some scientists believe that the development of flowering plants led to dinosaur extinction。
2019年托福写作：TPO42综合写作阅读题目.doc
2019 年托福写作： TPO42 综合写作阅读题目TPO42综合写作题目文本Integrated WritingGlass is a favored building material for modern architecture, yet it is also very dangerous for wild birds. Because they often cannot distinguish between glass andopen air, millions of birds are harmed every year when they tryto fly through glass windows. There are, however, several solutions that responsible businesses can use to preventinjuries to birds.One-Way GlassOne solution is to replace the regular, clear glass withone-way glass that is transparent in only one direction. The occupants of the building can see out, but birds and others cannot see in. If birds cannot see through a window, theywill understand that the glass forms a solid barrier and willnot try to fly through it.Colorful DesignsA second solution is to paint colorful lines or other designs on regular window glass. For example, a window could have a design of thin stripes painted over the glass. People would stillbe able to see through the openings in the design where thereis no paint, while birds would see the stripesand thus avoid trying to fly through the glass. Architectscan be encouraged to include colorful painted patterns onglass as part of the general design of buildings.Magnetic FieldThe third solution is to create an artificial magneticfield to guide birds away from buildings. Humans use aninstrument called a magnetic compass to determinedirections —either north, south, east, or west. Bird researchhas shown that birds have a natural ability to sense Earth’s magnetic fields; this ability works just like a compass, andit helps birds navigate in the right direction when they fly.A building in a bird flight path can be equipped withpowerful electromagnets that emit magnetic signals that steerbirds in a direction away from the building.DirectionsTPO42综合写作You have 20 minutes to plan and write your response.Your response will be judged on the basis of the quality of yourwriting and on how well your response presents the points in thelecture and their relationship to the reading passage. Typically,an effective response will be 150 to 225 words.Essay TopicTPO42综合写作Summarize the points made in the lecture, being sure toexplain how they cast doubt on the specific solutionsproposed in the reading passage.You must finish your answer in 20 minutes。
TPO阅读42文本答案翻译
TPO-42Geographic Isolation of SpeciesBiologist Ernst Mayr defined a species as “an actually or potentially interbreeding population that does notthe separation of a population with its gene pool (all of the genes in a population at any one time) from other populations of the same species, thereby preventing population interbreeding. With its gene pool isolated, a separate population canbeen a geographic barrier. This mode of evolving new species is called allopatric speciation.Many factors can isolate a population geographically. A mountain range may emerge and gradually split a population of organisms that can inhabit only lowland lakes, certain fish populations might become isolated in this way. Similarly, a creeping glacier may gradually divide a population, or a land bridge such as the Isthmus of Panama may form and separate the marine life in the ocean waters on either side.Too many words you don’t know? Look them up in《新托福TPO阅读词汇速查速记》!Wechat: geeqi0805How formidable must a geographic barrier be to keep populations apart? It depends on the ability of the organisms to move across barriers. Birds and coyotes can easily cross mountains and rivers. The passage of wind-blown tree pollen is also not hindered by such barriers, and the seeds of many plants may be carried back and forth on animals In contrast, small rodents may find a deep canyon or a wide river an effective barrier. For example, the Grand Canyon, in the southwestern United States, separate the range of the while-tailed antelop e squirrel from that of the closely related Harris’ antelope squirrel. Smaller, with a shorter tail that is white underneath, the white-tailed antelope squirrel inhabits deserts north of the canyon and west of the Colorado River in southern California Hams' antelope squirrel has a more limited range in deserts south of the Grand Canyon.Geographic isolation creates opportunities for new species to develop, but it does not necessarily lead to newbetween the isolated population and its parent population. The likelihood of allopatric speciation increases when a population is small as well as isolated, making it more likely than a large population to have its gene pool changed substantially. For example, in less than two million years, small populations of stray animals and plants from the SouthAmerican mainland to colonize the Galapagos Islands gave rise to all the species that now inhabit the islands.When oceanic islands are far enough apart to permit populations to evolve in isolation, but close enough to allow occasional dispersions to occur, they are effectively outdoor laboratories of evolution. The Galapagos island chain is one of the world’s greatest showcases of evolution. Each island was born from underwater volcanoes and was gradually covered by organisms derived from strays that rode the ocean currents and winds from other islands and continents. Organisms can also be carried to islands by other organisms, such as sea birds that travel long distances with seeds clinging to their feathers.The species on the Galapagos Islands today, most of which occur nowhere else, descended from organisms that floated, flew, or were blown over the sea from the South American mainland. For instance, the Galapagos island chainhas a total of thirteen species of closely related birds called Galapagos finches. These birds have many similarities but differ in their feeding habits and their beak type, which is correlated with what they eat. Accumulated evidence indicates that all thirteen finch species evolved from a single small population of ancestral birds that colonized one of the islands. Completely isolated on the island after migrating from the mainland, the founder population may have undergone significant changes in its gene pool and become a new species. ■Later, a few individuals of this new species may have been blown by storms to a neighboring island. ■Isolated on this second island, t he second founder population could have evolved into a second new species, which could later recolonize the island from which its founding population emigrated. ■Today each Galapagos island has multiple species of finches, with as many as ten on some islands. ■A. earlyB. crucialC. noticeableD. frequentA. bestB. usualC. firstD. actualYou enjoy the convenience of having all vocabulary questions listed as a separate part in《新托福TPO阅读词汇速查速记》.3. According to paragraph 1, allopatric speciation is possible whenA. a population contains all the different genes present in a species at a particular timeB. a population becomes isolated due to the presence of a geographic barrierC. genetic mixing begins to occur in previously separate populations of a speciesD. a species is successful in crossing a geographic barrier4. How is paragraph 2 related to paragraph 1?A. Paragraph 2 points out a number of ways in which the phenomenon of geographic isolation mentioned in paragraph 1 can occurB. Paragraph 2 identifies discoveries that led to the conclusion presented in paragraph 1 that geographic isolation has played a role in the origin of many speciesC. Paragraph 2 provides evidence supporting the statement in paragraph 1 that a population can follow its own evolutionary course once its gene pool becomes isolatedD. Paragraph 2 explains why the term “allopatric” was adopted to describe the method of speciation described in paragraph 15. In paragraph 3, the author contrasts a variety of organisms to illustrate which of the following points?A. Geographic barriers are less likely to keep apart populations of plants than populations of animalsB. Geographic barriers are more likely to keep apart populations of large organisms than populations of small organismsC. Some members of a species are able to cross geographic barriers, while other members of the same species are notD. The effectiveness of geographic barriers in keeping organisms apart depends on an organism’s ability to move across barriers6. Paragraph 3 supports the idea that white-tailed antelope squirrels and Hams' antelope squirrels have which of the following in common?A. They are the two smallest rodents now found in the southwestern United States.B. They have white coloring underneath their tailsC. They cannot cross the Grand CanyonD. They cannot survive in desert conditionsA. experiencesB. allowsC. preventsD. causes8. 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 informationA. Geographic isolation is sometimes but not always the reason for the creation of reproductive barriers between a parent population and the populations descended from itB. Genetic changes in a geographical isolated population do not necessarily make the population look different enough from its parent population to be considered a new speciesC. Geographical isolation allows the separated populations to evolve independently of each other and so can lead to the formation of new speciesD. Geographic isolation can lead to new species only if the gene pool of the isolated population changes enough to prevent it from reproducing with the parent population9. According to paragraph 4, why does the size of a population affect the likelihood of allopatric speciation?A. Because smaller populations are more likely than larger ones to become geographically isolatedB. Because the gene pool of a small isolated population is more likely to undergo substantial change than is the gene pool of a larger populationC. Because an isolated population can become a new species with substantially less change to its gene pool than would be required by a larger populationD. Because smaller populations are more likely to be made up of stray animals or plants than larger populations areA. were ableB. were forcedC. arrivedD. expanded11. Paragraph 5 supports the idea that the Galapagos island chain was able to become “one of the world's greatest showcases of evolution” primarily because ofA. the richness of the volcanic soil of each of the islands in the chainB. the distance of the individual islands from each other and from the mainlandC. the relativity long time it took for the islands to become covered by organismsD. the outdoor laboratories that scientists have built on the islands to study evolution12. According to paragraph 6, what is true about the thirteen species of Galapagos finches?A. All thirteen species are now found on most of the Galapagos IslandsB. All thirteen species are descended from the same population of ancestral birdsC. All thirteen species evolved on the island that was originally colonized by finches from the mainland.D. All thirteen species occur only in small, completely isolated populations.13. Look at the four squares [█] that indicate where the following sentence could be added to the passageThis process of speciation and colonization could have been repeated over and over again, gradually involving all the islands in the chain.Where would the sentence best fit? Click on a square to add the sentence to the passage.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. The question is worth 2 points.The geographic isolation of a population can result in the rise of a new species.●●●Answer Choices○ Isolation can result when a geographic barrier forms and splits a population or when a few organisms somehow get carried across an existing geographic barrier and form a new population○ Speciation is more likely when an isolated population is small because significant genetic changes are more likely to occur in a small population than in a large one○ Because of the geographic isolation of the Galapagos Islands, the species that now inhabit them have gene pools that have not changed very much since the islands were first populated.○ Fish populations are more easily isolated by geographic barriers than are populations of most other organisms because fish cannot move across areas where there is no water.○ The Galapagos Islands are well situated for speciation because they provide opportunities for population isolation while also making occasional dispersions between islands possible.○ Evidence indicates t hat the first organisms to reach the Galapagos Islands were probably a small population of finches that, in less than two million years of isolation, evolved into thirteen species.答案：1-5: B C B A D 6-10:C A D B A 11-14: B B C A B EIf you have any questions concerning the texts or answers, feel free to contact Wechat: geeqi0805.If you are tired of looking up TPO words in a dictionary, try《新托福TPO阅读词汇速查速记》!参考译文：物种的地理隔离生物学家厄恩斯特·迈尔将物种定义为“一个可以互相交配或可能互相交配的群体，但这个群体不能与其它生物交配，即便有交配的机会”。
2021年托福阅读PASSAGE 42 试题及答案
2021年托福阅读PASSAGE 42试题及答案PASSAGE 42Railroads reshaped the North American environment and reoriented North American behavior. "In a quarter of a century", claimed the Omaha Daily Republican in 1883, "they have made the people of the United States homogeneous, breaking through the peculiarities and provincialisms which marked separate and unmingling sections." The railroad simultaneously stripped the landscape of the natural resources, made velocity of transport and economy of scale necessary parts of industrial production, and carried consumer goods to households; it dispatched immigrants to unsettled places, drew emigrants away from farms and villages to cities, and sent men and guns to battle. It standardized time and travel, seeking to annihilate distance and space by allowing movement at any time and in any season or type of weather. In its grand and impressive terminals and stations, architects recreated historic Roman temples and public baths, French chateaus and Italian bell towers — edifices that people used as stages for many of everyday life's high emotions: meeting and parting, waiting and worrying, planning new starts or coming home.Passenger terminals, like the luxury express trains that hurled people over spots, spotlight the romance of railroading. (The twentieth-Century Limited sped between Chicago and New York in twenty hours by 1915). Equally important to everyday life were the slow freight trans chugging through industrial zones, the morning and evening commuter locals shuttling back ions and urban terminals, and the incessant comings and goings that occurred in the classifications, or switching, yards. Moreover, in addition to its being a transportation pathway equipped with a mammoth physical plant of tracks signals, crossings, bridges, and junctions, plus telegraph and telephone lines the railroad nurtured factory complexes, coat piles, warehouses, and generating stations, forming along its right-of-way what has aptly been called "the metropolitan corridor" of the American landscape.1. What does the passage mainly discuss?(A) The influence of ancient architecture on the design of railroad terminals(B) The importance of natural resources in the development of railroads(C) The railroad's impact on daily life in the United States in the nineteenth century(D) Technological improvements in the area of communication in the nineteenth century2. It can be inferred from the quote from the Omaha Daily Republican (line 2-4) that railroads(A) made all sections of the nation much wealthier(B) brought more unity to what had been a fragmented nation(C) reduced dependence on natural resources(D) had no effect on the environment of the United States3. The word "it" in line 7 refers to(A) transport(B) scale(C) production(D) railroad4. The word "drew" in line 8 is closest(A) obliged(B) designed(C) helped(D) attracted5. The word "annihilate" in line 9 is closest in meaning to(A) conquer(B) utilize(C) separate(D) mechanize6. The word "Moreover" in line 20 is closest in meaning to(A) consequently(B) furthermore(C) although(D) because7. All of the following were true of impressive passenger terminals EXCEPT:(A) Their architecture was influenced by the architecture of Europe.(B) Luxury express trains traveled between them.(C) They were usually located in small towns.(D) They were important to many commuters.8. According to the passage , which type of development lined the area along the metropolitan corridor?(A) Stores and shopping areas(B) Recreational areas(C) Industrial(D) Agricultural9. The word "aptly" in line 24 is closest in meaning to(A) appropriately(B) virtually(C) consistently(D) incessantly10. The author mentions the Twentieth-Century Limited as an example of(A) a freight train(B) a commuter train(C) a luxury train(D) an underground train11. The author gives a synonym for which of the following words?(A) homogeneous (line 3)(B) standardized (line 9)(C) temples (line 11)(D) classification(line 20)ANSWER KEYSPASSAGE 42 CBDDA BCCAC D。
metabolic options for dinosaurs托福原文
metabolic options for dinosaurs托福原文引言概述：恐龙是地球上曾经存在的最大型生物之一，它们拥有巨大的体型和强大的肌肉力量。
然而，要维持如此庞大的身体，恐龙需要有高效的新陈代谢方式。
本文将探讨恐龙可能的代谢途径，以及这些途径在其生存和生长中的重要性。
正文内容：1. 恐龙的代谢类型1.1 需氧代谢1.1.1 恐龙的呼吸系统1.1.2 恐龙的心血管系统1.1.3 恐龙的肌肉结构1.2 无氧代谢1.2.1 恐龙的骨骼结构1.2.2 恐龙的能量储备1.2.3 恐龙的生长速度2. 恐龙的能量需求2.1 食物摄入2.1.1 恐龙的食性2.1.2 恐龙的消化系统2.1.3 恐龙的进食习惯2.2 能量消耗2.2.1 恐龙的运动能力2.2.2 恐龙的体温调节2.2.3 恐龙的行为习惯3. 恐龙的代谢适应3.1 体型和代谢的关系3.1.1 恐龙的体型对代谢的影响3.1.2 恐龙的代谢对体型的限制3.1.3 恐龙的代谢适应能力3.2 环境适应3.2.1 恐龙的生活环境3.2.2 恐龙的代谢适应与环境的关系3.2.3 恐龙的代谢适应对环境的影响3.3 进化适应3.3.1 恐龙的代谢进化3.3.2 恐龙的代谢适应与进化的关系3.3.3 恐龙代谢进化的影响总结：恐龙的代谢途径是其生存和生长的关键因素之一。
通过对恐龙的代谢类型、能量需求和代谢适应的研究，我们可以更好地理解恐龙的生态和进化。
未来的研究还可以进一步探索恐龙的代谢机制，以及其与其他生物的关系，为我们揭示恐龙的生活方式和生态系统提供更多的信息。
托福阅读真题第42篇TheEvolutionofPlantRoots
托福阅读真题第42篇TheEvolutionofPlantRoots托福阅读真题第42篇The Evolution of Plant RootsThe Evolution of Plant RootsRoots are essential to the development of large plants because they provide a means of anchoring and maintaining an upright position.Most land plants are literally rooted to the spot.Roots also play a key role in water and nutrient acquisition.More significantly still, roots have a tremendous impact on the environment. They can break up rock, bind loose particles together, and prov idea conduit for the movement of water and dissolved minerals,all of which are essential to the development of soils.In piecing together a fossil plant to form a conceptual whole, it is usually the rooting system that remains the final piece in the puzzle. It is often the case that roots are poorly studied or completely unknown.Although the fossil record of roots is therefore less complete than that of other plant organ systems, it is possible to discern some general trends.The earliest land plants, like modern mosses and liverworts,did not have well-developed root systems.These plants simply bore absorbing hairlike cells on stems and leaves that grew flat along the ground.From their fossils,some very early plants are known to have borne branches that appear to be specially modified for rooting. In other cases, roots were able to form from dormant buds on aerial stems.Fungi are also known to have played a key role in these early rooting systems, as they do in modern plants.Fungal symbionts—fungi that live in mutually beneficial relationships with another organism-have been recorded in the petrified plants of the 400million-year-old Rhynie Chert fossil sitein Scotland, demonstrating a link with mycorrhizal fungi that goes back to the dawn of the land flora.These tiny, shallow rooting systems were adequate for small plants (30-50 centimeters tall), but larger organisms required something more substantial.By the Late Devonian and Early Carboniferous eras (385 to 300 million years ago), an enormous variety of rooting structures had evolved.The evolution of large erect plants, and in particular trees,placed increasing demands upon the anchoring and supply functions of roots.These problems were solved mainly through the development of more extensive underground systems.The evolution of the cambium, the layer of living cells between wood and bark,enabled continuous perennial growth and long-term survival of roots in soils.One important consequence of all this was that there was a progressive and massive increase in root biomass during the Devonian, which had an enormous impact on the development of soils. Prior to the Devonian,soils, if developed at all, are thought to have been predominantly thin and of microbial origin. By the Middle Devonian,soil penetration depths of roots were still shallow(less than 20 centimeters), but this increased to 1 meter or more as forests spread.The diversity of soils also increased.This change was brought about by root-induced weathering and mixing. By the end of the Devonian, there was an increase in soil clay content,structure,and differentiation into distinct layers—a development that correlated with increases in depth of root penetration. Soils with modern profiles(series of layers) are recognizable at this time.The impact of roots on the environment extends beyond their immediate effects on the development of soils.The presenceof roots in soils increases the natural weathering of calcium and magnesium silicate minerals.This apparently mundane fact turns out to have extremely important consequences for climate and temperature globally. Under natural circumstances, calcium and magnesium silicates react chemically with a dissolved form of the gas carbon dioxide (a process referred to as weathering), which comes from the atmosphere.This produces calcium and magnesium carbonates,which are transferred through the groundwater system to rivers and ultimately to the oceans, where they accumulate in the form of limestone and dolomite rock.Across the surface of the Earth, these chemical reactions occur on a vast scale, removing carbon dioxide gas from the atmosphere and locking it up as carbonate in rock formations. This reduces the so-called greenhouse effect, which leads to lower global temperatures. In other words, the widespread development of roots in land plants affected the chemistry of the atmosphere and the oceans, which, summed over millions of years,added up to changes in climate on a global scale.1.Roots are essential to the development of large plants because they provide a means of anchoring and maintaining an upright position.Most land plants are literally rooted to the spot.Roots also play a key role in water and nutrient acquisition.More significantly still, roots have a tremendous impact on the environment. They can break up rock, bind loose particles together, and prov idea conduit for the movement of water and dissolved minerals,all of which are essential to the development of soils.2.In piecing together a fossil plant to form a conceptual whole, it is usually the rooting system that remains the final piecein the puzzle. It is often the case that roots are poorly studied or completely unknown.Although the fossil record of roots is therefore less complete than that of other plant organ systems, it is possible to discern some general trends.The earliest land plants, like modern mosses and liverworts,did not have well-developed root systems.These plants simply bore absorbing hairlike cells on stems and leaves that grew flat along the ground.From their fossils,some very early plants are known to have borne branches that appear to be specially modified for rooting. In other cases, roots were able to form from dormant buds on aerial stems.Fungi are also known to have played a key role in these early rooting systems, as they do in modern plants.Fungal symbionts—fungi that live in mutually beneficial relationships with another organism-have been recorded in the petrified plants of the 400million-year-old Rhynie Chert fossil site in Scotland, demonstrating a link with mycorrhizal fungi that goes back to the dawn of the land flora.These tiny, shallow rooting systems were adequate for small plants (30-50 centimeters tall), but larger organisms required something more substantial.3.In piecing together a fossil plant to form a conceptual whole, it is usually the rooting system that remains the final piece in the puzzle. It is often the case that roots are poorly studied or completely unknown.Although the fossil record of roots is therefore less complete than that of other plant organ systems, it is possible to discern some general trends.The earliest land plants, like modern mosses and liverworts,did not have well-developed root systems.These plants simply bore absorbing hairlike cells on stems and leaves that grew flat along theground.From their fossils,some very early plants are known to have borne branches that appear to be specially modified for rooting. In other cases, roots were able to form from dormant buds on aerial stems.Fungi are also known to have played a key role in these early rooting systems, as they do in modern plants.Fungal symbionts—fungi that live in mutually beneficial relationships with another organism-have been recorded in the petrified plants of the 400million-year-old Rhynie Chert fossil site in Scotland, demonstrating a link with mycorrhizal fungi that goes back to the dawn of the land flora.These tiny, shallow rooting systems were adequate for small plants (30-50 centimeters tall), but larger organisms required something more substantial.4.By the Late Devonian and Early Carboniferous eras (385 to 300 million years ago), an enormous variety of rooting structures had evolved.The evolution of large erect plants, and in particular trees,placed increasing demands upon the anchoring and supply functions of roots.These problems were solved mainly through the development of more extensive underground systems.The evolution of the cambium, the layer of living cells between wood and bark,enabled continuous perennial growth and long-term survival of roots in soils.5.One important consequence of all this was that there wasa progressive and massive increase in root biomass during the Devonian, which had an enormous impact on the development of soils. Prior to the Devonian,soils, if developed at all, are thought to have been predominantly thin and of microbial origin. By the Middle Devonian,soil penetration depths of roots were stillshallow(less than 20 centimeters), but this increased to 1 meter or more as forests spread.The diversity of soils also increased.This change was brought about by root-induced weathering and mixing. By the end of the Devonian, there was an increase in soil clay content,structure,and differentiation into distinct layers—a development that correlated with increases in depth of root penetration. Soils with modern profiles(series of layers) are recognizable at this time.6.One important consequence of all this was that there wasa progressive and massive increase in root biomass during the Devonian, which had an enormous impact on the development of soils. Prior to the Devonian,soils, if developed at all, are thought to have been predominantly thin and of microbial origin. By the Middle Devonian,soil penetration depths of roots were still shallow(less than 20 centimeters), but this increased to 1 meter or more as forests spread.The diversity of soils also increased.This change was brought about by root-induced weathering and mixing. By the end of the Devonian, there was an increase in soil clay content,structure,and differentiation into distinct layers—a development that correlated with increases in depth of root penetration. Soils with modern profiles(series of layers) are recognizable at this time.7.The impact of roots on the environment extends beyond their immediate effects on the development of soils.The presence of roots in soils increases the natural weathering of calcium and magnesium silicate minerals.This apparently mundane fact turns out to have extremely important consequences for climate and temperature globally. Under natural circumstances, calcium andmagnesium silicates react chemically with a dissolved form of the gas carbon dioxide (a process referred to as weathering), which comes from the atmosphere.This produces calcium and magnesium carbonates,which are transferred through the groundwater system to rivers and ultimately to the oceans, where they accumulate in the form of limestone and dolomite rock.Across the surface of the Earth, these chemical reactions occur on a vast scale, removing carbon dioxide gas from the atmosphere and locking it up as carbonate in rock formations. This reduces the so-called greenhouse effect, which leads to lower global temperatures. In other words, the widespread development of roots in land plants affected the chemistry of the atmosphere and the oceans, which, summed over millions of years,added up to changes in climate on a global scale.8.The impact of roots on the environment extends beyond their immediate effects on the development of soils.The presence of roots in soils increases the natural weathering of calcium and magnesium silicate minerals.This apparently mundane fact turns out to have extremely important consequences for climate and temperature globally. Under natural circumstances, calcium and magnesium silicates react chemically with a dissolved form of the gas carbon dioxide (a process referred to as weathering), which comes from the atmosphere.This produces calcium and magnesium carbonates,which are transferred through the groundwater system to rivers and ultimately to the oceans, where they accumulate in the form of limestone and dolomite rock.Across the surface of the Earth, these chemical reactions occur on a vast scale, removing carbon dioxide gas from the atmosphere and locking it up as carbonate in rock formations.This reduces the so-called greenhouse effect, which leads to lower global temperatures. In other words, the widespread development of roots in land plants affected the chemistry of the atmosphere and the oceans, which, summed over millions of years,added up to changes in climate on a global scale.9.Roots are essential to the development of large plants because they provide a means of anchoring and maintaining an upright position.⬛Most land plants are literally rooted to the spot.⬛Roots also play a key role in water and nutrient acquisition.⬛More significantly still, roots have a tremendous impact on the environment. ⬛They can break up rock, bind loose particles together, and prov idea conduit for the movement of water and dissolved minerals,all of which are essential to the development of soils.10.答案如下：.42篇The Evolution of Plant Roots。
托福阅读tpo48-2原文+译文+题目+答案+背景知识
目录tpo48Passage2:Determining Dinosaur Diet (1)译文：探究恐龙饮食 (2)练习题目 (3)答案 (9)文章小结题解析 (9)背景知识 (9)tpo48Passage2:Determining Dinosaur Diet①Determining what extinct dinosaurs ate is difficult,but we can infer some aspects of their dietary preferences.Traditionally,this information has been derived from direct evidence,such as stomach contents,and indirect evidence,such as establishing a correlation between particular body characteristics and diets of living animals and then inferring habits for dinosaurs.②Animals such as house cats and dogs have large,stabbing canine teeth at the front of the mouth and smaller,equally sharp teeth farther back in their jaws.Many of these animals are also armed with sharp claws.The advantage of teeth and claws as predatory tools is obvious.Now consider animals like cows,horses,rabbits,and mice. These animals have flat teeth at the back of the jaw that are analogous to and have the same function as grindstones.Unlike the meat-slicing and stabbing teeth of carnivores,the teeth of these animals grind and shred plant material before digestion.③More clues exist in other parts of the skull.The jaw joint of carnivores such as dogs and cats has the mechanical advantage of being at the same level as the tooth row, allowing the jaws to close with tremendous speed and forcing the upper teeth to occlude against the lower teeth with great precision.In herbivorous animals,rapid jaw closure is less important.Because the flat teeth of herbivores work like grindstones,however,the jaws mush move both side to side and front to back.The jaw joints of many advanced herbivores,such as cows,lie at a different level than the tooth row,allowing transverse tearing,shredding,and compression of plant material. If we extend such observations to extinct dinosaurs,we can infer dietary preferences (such as carnivory and herbivory),even though we cannot determine the exact diet. The duck-billed dinosaurs known as hadrosaurs are a good example of a group whose jaw joint is below the level of the tooth row,which probably helped them grind up tough,fibrous vegetation.④Paleontologists would like to be much more specific about a dinosaur’s diet than simply differentiating carnivore from herbivore.This finer level of resolution requires direct fossil evidence of dinosaur meals.Stomach contents are only rarely preserved, but when present,allow us to determine exactly what these animals were eating.⑤In the stomach contents of specimens of Coelophysis(a small,long-necked dinosaur)are bones from juvenile animals of the same species.At one time,thesewere thought to represent embryonic animals,suggesting that this small dinosaur gave birth to live young rather than laying eggs.Further research indicated that the small dinosaurs were too large and too well developed to be prehatchling young.In addition,the juveniles inside the body cavity were of different sizes.All the evidence points to the conclusion that these are the remains of prey items and that,as an adult,Coelophysis was at least in part a cannibal.⑥Fossilized stomach contents are not restricted to carnivorous dinosaurs.In a few rare cases,most of them“mummies”(unusually well preserved specimens), fossilized plant remains have been found inside the body cavity of hadrosaurs.Some paleontologists have argued that these represent stream accumulations rather than final meals.The best known of these cases is the second Edmontosaurus mummy collected by the Sternbergs.In the chest cavity of this specimen,which is housed in the Senckenberg Museum in Germany,are the fossil remains of conifer needles, twigs,seeds,and fruits.Similar finds in Corythosaurus specimens from Alberta, Canada,have also been reported,indicating that at least two kinds of Late Cretaceous hadrosaurs fed on the sorts of tress that are common in today’s boreal woodlands.⑦A second form of direct evidence comes from coprolites(fossilized bodily waste). Several dinosaur fossil localities preserve coprolites.Coprolites yield unequivocal evidence about the dietary habits of dinosaurs.Many parts of plants and animals are extremely resistant to the digestive systems of animals and pass completely through the body with little or no alteration.Study of coprolites has indicated that the diets of some herbivorous dinosaurs were relatively diverse,while other dinosaurs appear to have been specialists,feeding on particular types of plants.The problem with inferring diets from coprolites is the difficulty in accurately associating a particular coprolite with a specific dinosaur.译文：探究恐龙饮食①确定灭绝的恐龙吃什么是困难的，但我们可以推断出他们的饮食偏好的某些方面。