2019年托福写作：TPO42综合写作阅读题目.doc

Callisto and GanymedeFrom 1996 to 1999, the Galileo spacecraft passed through the Jovian system, providing much information about Jupiter's satellites. Callisto, the outermost of Jupiter's four largest satellites, orbits the planet in seventeen days at a distance from Jupiter of two million kilometers. Like our own Moon. Callisto rotates in the same period as it revolves, so it always keeps the same face toward Jupiter. Its noontime surface temperature is only about -140°C, so water ice is stable on its surface year-round. Callisto has a diameter of 4.820 kilometers, almost the same as that of Mercury. Its mass is only one-third as great, which means its density must be only one-third as great as well. This tells us that Callisto has far less of the rocky metallic materials found in the inner planets and must instead be an icy body through much of its interior.Callisto has not fully differentiated, meaning separated into layers of different density materials. Astronomers can tell that it lacks a dense core from the details of its gravitational pull on the Galileo spacecraft during several very close flybys. This fact surprised scientists, who expected that all the big icy moons would be differentiated. It is much easier for an icy body to differentiate than for a rocky one, since the melting temperature of ice is so low. Only a little heating will soften the ice and get the process started, allowing the rock and metal to sink to the center and the slushy ice to float to the surface. Y et Callisto seems to have frozen solid before the process of differentiation was complete.Like our Moon's highlands, the surface of Callisto is covered with impact craters. The survival of these craters tells us that an icy object can form and retain impact craters m its surface. In thinking of ice so far from the Sun, it is important not to judge its behavior from that of the much warmer ice we know on Earth; at the temperatures of the outer solar system, ice on the surface is nearly as hard as rock, and behaves similarly. Ice on Callisto does not deform or flow like ice in glaciers on Earth. Callisto is unique among the planet-sized objects of the solar system in its absence of interior forces to drive geological evolution. The satellite was born dead and has remained geologically dead for more than four billion years.Ganymede, another of Jupiter's satellites and the largest in our solar system, is also cratered, but less so than Callisto. About one-quarter of its surface seems to be as old and heavily cratered; the rest formed more recently, as we can tell by the sparse covering of impact craters as well as the relative freshness of the craters. Ganymede is a differentiated world, like the terrestrial planets. Measurements of its gravity field tell us that the rock and metal sank to form a core about the size of our Moon, with a mantle and crust of ice floating above it. In addition, the Galileo spacecraft discovered that Ganymede has a magnetic field, the signature of a partially molten interior. Ganymede is not a dead world, but rather a place of continuing geological activity powered by an internal heat source. Much of its surface may be as young as half a billion years.The younger terrain is the result of tectonic and volcanic forces Some features formed when the crust cracked, flooding many of the craters with water from the interior. Extensive mountain ranges were formed from compression of the crust, forming long ridges with parallel valleys spaced one to two kilometers apart. In some places older impact craters were split and pulled apart. There are even indications of large-scale crustal movements that are similar to the plate tectonics of Earth.Why is Ganymede different from Callisto? Possibly the small difference in size and internal heating between the two led to this divergence in their evolution. But more likely the gravity of Jupiter is to blame for Ganymede's continuing geological activity. Ganymede is close enough to Jupiter that tidal forces from the giant planet may have episodically heated its interior and triggered major convulsions on its crust.paragraph 1From 1996 to 1999, the Galileo spacecraft passed through the Jovian system, providing much information about Jupiter's satellites. Callisto, the outermost of Jupiter's four largest satellites, orbits the planet in seventeen days at a distance from Jupiter of two million kilometers. Like our own Moon. Callisto rotates in the same period as it revolves, so it always keeps the same face toward Jupiter. Its noontime surface temperature is only about -140°C, so water ice is stable on its surface year-round. Callisto has a diameter of 4.820 kilometers, almost the same as that of Mercury. Its mass is only one-third as great, which means its density must be only one-third as great as well. This tells us that Callisto has far less of the rocky metallic materials found in the inner planets and must instead be an icy body through much of its interior.1.According to paragraph 1, which of the following statements about Callisto is true?A.It is the satellite closest to Jupiter's surfaceB.Its surface temperature is constant at all times of the day.C. It has the same mass and diameter as the planet MercuryD. It completes one rotation every seventeen days.2. According to paragraph 1, how do scientists know that Callisto is made up largely of ice?A. A sample of its interior was taken by the Galileo spacecraft in the late 1990sB. It has too low a density to contain much rocky metallic materialC. With a noontime surface temperature of only about .140° C. the ice on it never meltsD. All of the bodies in the Jovian system are icy, because they are so far from the Sun.paragraph 2Callisto has not fully differentiated, meaning separated into layers of different density materials. Astronomers can tell that it lacks a dense core from the details of its gravitational pull on the Galileo spacecraft during several very close flybys. This fact surprised scientists, who expected that all the big icy moons would be differentiated. It is much easier for an icy body to differentiate than for a rocky one, since the melting temperature of ice is so low. Only a little heating will soften the ice and get the process started, allowing the rock and metal to sink to the center and the slushy ice to float to the surface. Y et Callisto seems to have frozen solid before the process of differentiation was complete.3.Why does the author provide the information that “It is much easier for an icy body to differentiate than for a rocky one”?A. To support the claim that all of the big icy moons are differentiatedB. To suggest that Callisto may be a rocky body rather than an icy oneC. To explain why scientists expected Callisto to be differentiatedD. To refute the claim that Callisto could not differentiate because it was frozen solid4.All of the following questions are answered in paragraph 2 EXCEPT:A.Why was Callisto frozen solid before differentiation was complete?B.What allows the process of differentiation to get started?C. Why is it easier for an icy body to differentiate than a rocky one?D. How do astronomers know that Callisto lacks a dense core?paragraph 3Like our Moon's highlands, the surface of Callisto is covered with impact craters. The survival of these craters tells us that an icy object can form and retain impact craters m its surface. In thinking of ice so far from the Sun, it is important not to judge its behavior from that of the much warmer ice we know on Earth; at the temperatures of the outer solar system, ice on the surface is nearly as hard as rock, and behaves similarly. Ice on Callisto does not deform or flow like ice in glaciers on Earth. Callisto is unique among the planet-sized objects of the solar system in its absence of interior forces to drive geological evolution. The satellite was born dead and has remained geologically dead for more than four billion years.5. 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.A. It should not be assumed that surface ice has the same characteristics wherever it is foundB. Surface ice and rock are much more similar in temperature in the outer solar system than they are on Earth.C. The further away surface ice is from the Sun, the more its temperature differs from that of the warmer ice on EarthD. In the cold of the outer solar system, surface ice is so hard it behaves more like rock than like the warmer ice on Earth6.According to paragraph 3, how is Callisto different from all other planet-sized objects in the solar system?A. It can form and retain impact craters on its icy surfaceB. It has ice glaciers that do not flow or deform.C. It has never had the interior forces required for geological evolution.D. It is more than four billion years old.paragraph 4Ganymede, another of Jupiter's satellites and the largest in our solar system, is also cratered, but less so thanCallisto. About one-quarter of its surface seems to be as old and heavily cratered; the rest formed more recently, as we can tell by the sparse covering of impact craters as well as the relative freshness of the craters. Ganymede is a differentiated world, like the terrestrial planets. Measurements of its gravity field tell us that the rock and metal sank to form a core about the size of our Moon, with a mantle and crust of ice floating above it. In addition, the Galileo spacecraft discovered that Ganymede has a magnetic field, the signature of a partially molten interior. Ganymede is not a dead world, but rather a place of continuing geological activity powered by an internal heat source. Much of its surface may be as young as half a billion years.7.The word “signature” in the passage is closest in meaning toA.primary causeB.end resultC.identifying markD.by-product8. According to paragraph 4, each of the following provides evidence about Ganymede's interior EXCEPTA. Ganymede's large sizeB. measurements of Ganymede's gravity fieldC. the fact that Ganymede has a magnetic fieldD. the fact that Ganymede continues to be geologically activeparagraph 5The younger terrain is the result of tectonic and volcanic forces Some features formed when the crust cracked, flooding many of the craters with water from the interior. Extensive mountain ranges were formed from compression of the crust, forming long ridges with parallel valleys spaced one to two kilometers apart. In some places older impact craters were split and pulled apart. There are even indications of large-scale crustal movements that are similar to the plate tectonics of Earth.9.The word “Extensive” in the passage is closet in meaning toA.UnusualrgeC.NewD.Steep10. Paragraph 5 supports each of the following statements about Ganymede EXCEPT:A. All water on it has always been frozen solid.B. There is evidence that part of its crust once broke openC. Its crust has been subject to forces that have created mountains and valleys.D. Some of its older craters have been split apart by more recent geological activityparagraph 6Why is Ganymede different from Callisto? Possibly the small difference in size and internal heating between the two led to this divergence in their evolution. But more likely the gravity of Jupiter is to blame for Ganymede's continuing geological activity. Ganymede is close enough to Jupiter that tidal forces from the giant planet may have episodically heated its interior and triggered major convulsions on its crust.11. According to paragraph 6, the differences in how Callisto and Ganymede evoked are most probably due to differences in theirA. size and internal heatingB. distance from JupiterC. chemical and physical compositionD. age12.Look at the four squares [■] that indicate where the following sentence could be added to the passage.The difference between Ganymede and Callisto, however, extend much further below the surface of the satellites.Where would the sentence best fit? Click on square [■] to add the sentence to the passageGanymede, another of Jupiter's satellites and the largest in our solar system, is also cratered, but less so than Callisto. [■] About one-quarter of its surface seems to be as old and heavily cratered; the rest formed more recently, as we can tell by the sparse covering of impact craters as well as the relative freshness of the craters. [■] Ganymede is a differentiated world, like the terrestrial planets. [■] Measurements of its gravity field tell us that the rock and metal sank to form a core about the size of our Moon, with a mantle and crust of ice floating above it. [■] In addition, the Galileo spacecraft discovered that Ganymede has a magnetic field, the signature of a partially molten interior. Ganymede is not a dead world, but rather a place of continuing geological activity powered by an internal heat source. Much of its surface may be as young as half a billion years.13. 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 because they 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 TextBetween 600 B.C. and 450 B.C., Athens changed the distribution of political power betweenthe aristocracy and ordinary citizens.CallistoGanymede阅读三Answer ChoicesA. It has a core that consists mainly of rock and metal.B. It may have formed as recently as half a billion years agoC. Its interior is not fully solidD. Its evolution has probably been strongly influenced by Jupiter's gravityE. It always keeps the same face toward Jupiter as it orbits the planetF. Its crust is covered by slow-moving glaciersG. Its entire surface is heavily cratered。

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。

When it comes to the question that whether a worker like to have different types of tasks a day or to do some similar task for the whole day, there is always some heat debates among the public. Some people may claim that doing different types of works is more attractive because they are less likely to get tired off if they could switch their focus for one task to another. However, as for me, I would like to only focus on similar tasks for the all day. My reasons are listed below.First of all, focusing on similar tasks could help me to do some work repeatedly and spare your time and effort on (一些特定的技巧)（要把原因讲一下）sharpen some particular professional skill and thus be more specialized in some field. Under such circumstances, I could significantly enhance my working efficiency. Take myself as an example. 用艺术/科技方面来举例（例子要将原因）Under such circumstances, I gradually become the expert in this particular field and quickly get promoted as the director specialized in Bank Account in the company. Therefore, it is of great importance to focus on a particular task, which helps you to get improved effectively.（影响，你可能在这个专业就很厉害）（概述要论点的原因和影响都要写，例子也是。

在托福写作练习过程中，相信TPO材料中的作文题目都会是大家的首选练习材料。

所以小编给考生们带来了托福写作TPO42，希望可以帮助广大托福考生轻松备考托福。

托福TPO42综合写作TASK 1 Integrated WritingGlass is a favored building material for modern architecture, yet it isalso very dangerous for wild birds. Because they often cannot distinguishbetween glass and open air, millions of birds are harmed every year when theytry to fly through glass windows. There are, however, several solutions thatresponsible businesses can use to prevent injuries to birds.One-Way GlassOne solution is to replace the regular, clear glass with one-way glass thatis 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 will not try to flythrough it.Colorful DesignsA second solution is to paint colorful lines or other designs on regularwindow glass. For example, a window could have a design of thin stripes paintedover the glass. People would still be able to see through the openings in thedesign where there is no paint, while birds would see the stripes and thus avoidtrying to fly through the glass. Architects can be encouraged to includecolorful painted patterns on glass as part of the general design ofbuildings.Magnetic FieldThe third solution is to create an artificial magnetic field to guide birds away from buildings. Humans use an instrument called a magnetic compass to determine directions—either north, south, east, or west. Bird research has shown that birds have a natural ability to sense Earth’s magnetic fields; this ability works just like a compass, and it helps birds navigate in the right direction when they fly. A building in a bird flight path can be equipped with powerful electromagnets that emit magnetic signals that steer birds in a direction away from the building.DirectionsYou have 20 minutes to plan and write your response. Your response will be judged on the basis of the quality of your writing and on how well your response presents the points in the lecture and their relationship to the reading passage. Typically, an effective response will be 150 to 225 words.Essay TopicSummarize the points made in the lecture, being sure to explain how theycast doubt on the specific solutions proposed in the reading passage.You must finish your answer in 20 minutes托福TPO42独立写作TASK 2 Independent WritingDirectionsRead the question below. You have 30 minutes to plan, write, and reviseyour essay. Typically, an effective response will contain a minimum of 300 words.Question:。

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：TPO43综合写作阅读题目TPO43综合写作题目文本Agnostids were a group of marine animals that became extinct about 450 million years ago. Agnostid fossils can be found in rocks in many areas around the world. From thefossil remains, we know that agnostids were primitive arthropods-relatives of modern-day insects. However, the fossil information does not allow paleontologists to determine with certainty what agnostids ate or how they behaved. There are several different theories about how agnostids may have lived.Free-Swimming PredatorsFirst, the agnostids may have been free-swimming predators that hunted smaller animals. It is known that other types of primitive arthropods were strong swimmers and active predators, so it is reasonable that the agnostids may have lived that way as well And while the agnostids were small, sometimes just six millimeters long, there were plenty of smaller organisms in the ancient ocean for them to prey on.Seafloor DwellersSecond, they may have dwelled on the seafloor. Again, there are examples of other types of primitive arthropods living this way, so it is possible that agnostids did too. On the seafloor they would have survived by scavenging dead organisms or by grazing on bacteria.ParasitesThird, there is the possibility that the agnostids were parasites, living on and feeding off larger organisms. One reason that this seems possible is that there are many species of modern-day arthropods that exist as parasites, such as fleas, ticks, and mites. The agnostids might have lived on primitive fish or even on other, larger arthropods.TPO43综合写作Directions： You have 20 minutes to plan and write your response. Your response will be judged on the basis of the quality of your writing and on how well your response presents the points in the lecture and their relationship to the reading passage. Typically, an effective response will be 150 to 225 words.TPO43综合写作Question： Summarize the points made in the lecture, being sure to explain how they challenge thespecific theories presented in the reading passage.。

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Callisto and Ganymede From 1996 to 1999,the Galileo spacecraft passed through the Jovian system,providing much information about Jupiter's satellites.Callisto,the outermost of Jupiter's four largest satellites,orbits the planet in seventeen days at a distance from Jupiter of two million kilometers.Like our own Moon.Callisto rotates in the same period as it revolves,so it always keeps the same face toward Jupiter.Its noontime surface temperature is only about-140°C,so water ice is stable on its surface year-round.Callisto has a diameter of 4.820 kilometers,almost the same as that of Mercury.Its mass is only one-third as great,which means its density must be only one-third as great as well.This tells us that Callisto has far less of the rocky metallic materials found in the inner planets and must instead be an icy body through much of its interior. Callisto has not fully differentiated,meaning separated into layers of different density materials.Astronomers can tell that it lacks a dense core from the details of its gravitational pull on the Galileo spacecraft during several very close flybys.This fact surprised scientists,who expected that all the big icy moons would be differentiated.It is much easier for an icy body to differentiate than for a rocky one,since the melting temperature of ice is so low.Only a little heating will soften the ice and get the process started,allowing the rock and metal to sink to the center and the slushy ice to float to the surface.Yet Callisto seems to have frozen solid before the process of differentiation was complete. Like our Moon's highlands,the surface of Callisto is covered with impact craters.The survival of these craters tells us that an icy object can form and retain impact craters m its surface.In thinking of ice so far from the Sun,it is important not to judge its behavior from that of the much warmer ice we know on Earth;at the temperatures of the outer solar system,ice on the surface is nearly as hard as rock,and behaves similarly.Ice on Callisto does not deform or flow like ice in glaciers on Earth.Callisto is unique among the planet-sized objects of the solar system in its absence of interior forces to drive geological evolution.The satellite was born dead and has remained geologically dead for more than four billion years. Ganymede,another of Jupiter's satellites and the largest in our solar system,is also cratered,but less so than Callisto.About one-quarter of its surface seems to be as old and heavily cratered;the rest formed more recently,as we can tell by the sparse covering of impact craters as well as the relative freshness of the craters.Ganymede is a differentiated world,like the terrestrial planets.Measurements of its gravity field tell us that the rock and metal sank to form a core about the size of our Moon,with a mantle and crust of ice floating aboveit.In addition,the Galileo spacecraft discovered that Ganymede has a magnetic field,the signature of a partially molten interior.Ganymede is not a dead world,but rather a place of continuing geological activity powered by an internal heat source.Much of its surface may be as young as half a billion years. The younger terrain is the result of tectonic and volcanic forces Some features formed when the crust cracked,flooding many of the craters with water from the interior.Extensive mountain ranges were formed from compression of the crust,forming long ridges with parallel valleys spaced one to two kilometers apart.In some places older impact craters were split and pulled apart.There are even indications of large-scale crustal movements that are similar to the plate tectonics of Earth. Why is Ganymede different from Callisto?Possibly the small difference in size and internal heating between the two led to this divergence in their evolution.But more likely the gravity of Jupiter is to blame for Ganymede's continuing geological activity.Ganymede is close enough to Jupiter that tidal forces from the giant planet may have episodically heated its interior and triggered major convulsions on its crust. paragraph 1 From 1996 to 1999,the Galileo spacecraft passed through the Jovian system,providing much information about Jupiter's satellites.Callisto,the outermost of Jupiter's four largest satellites,orbits the planet in seventeen days at a distance from Jupiter of two million kilometers.Like our own Moon.Callisto rotates in the same period as it revolves,so it always keeps the same face toward Jupiter.Its noontime surface temperature is only about-140°C,so water ice is stable on its surface year-round.Callisto has a diameter of 4.820 kilometers,almost the same as that of Mercury.Its mass is only one-third as great,which means its density must be only one-third as great as well.This tells us that Callisto has far less of the rocky metallic materials found in the inner planets and must instead be an icy body through much of its interior. 1.According to paragraph 1,which of the following statements about Callisto is true? 【事实信息题】 A.It is the satellite closest to Jupiter's surface B.Its surface temperature is constant at all times of the day. C.It has the same mass and diameter as the planet Mercury。

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。

Three solutions are proposed in the reading passage to prevent injuries caused by glass used to birds in the buildings. However, the professor in the lecture contradicts all of them.First of all, the author argues that the regular, clear glass can be replaced byone-way glass, sothat the birds can not see through fromoutside andthus will notfly through the glass window. By contrast, the professor refutes this solution by claimingthat the one-way glass actually works as a mirror when seen fromoutside,whose impact will be as bad as the regular glass because birds do not understand the functions of mirror, on whose surface trees and the sky will be reflected, sobirds will think it is the same as the natural world.Second, the author states that architects can paint colorful lines and designson regular glass window, and when birds see the stripes from outside, they willavoid flying through the window. On the contrary, the professor maintains that even with colorful designs there will be unpainted openings on the window looking just like open holes, so birds may still fly through those holes. In order to prevent it fromhappening, the unpaintedspaces must be small enough. But in thiscase, the room will be too dark.Third, the reading proposes that humans can install artificial magnetic field on buildingtohelpbirds navigate away frombuildings. However, the professor insiststhat birds actually use magnetic signals to navigate only when they migrate a longway such as when they migrate fromcoldareas towarmareas duringspring. But ifthey are on a short trip, they wouldrely on their eyes to navigate. So the magneticdevice will not be effective, either.。

tpo42独立写作范文There are different standpoints regarding the happiness from the work. Some argue that workers would gain more satisfaction from doing different types of tasks while others hold the opposite idea that to do the same task leads them to be happier. In fact, it is hard to judge and up to the context of the work.Obviously, the majority of people are reluctant to repeat their action mechanically, because they cannot endure the tediousness created by the same work. Trying to do different types of tasks is beneficial for them to keep the motivation of job and is easy to satisfy themselves with achieving success in varied domains. Meanwhile, however, other consequences as a result from dissimilar sorts of work are supposed to be taken into account as well.The different types of tasks would make it impossible for workers to be happy sometimes: they coerce these people to face new challenges and it costs more time to acquaint every kind of tasks which even would be changed definitely in the second day. Except few extremely bold people, a huge number of workers willfeel quite stressful when something is completely new for them. Further, the same type of task doesn’t mean the context of the job is the same. People are likely to suffer from varied kinds of in the daily work. An architect should do several different plans for one project. Even though they draw a window for one building’s , they have to establish dozens of models of windows to match the whole genre. Besides, if their work does not f ulfill their customers’ demands, the architects have no choice but to redraw the . This type of work on some stage can also be called working repeatedly, whereas the context is definitely different and filled with challenges. It affords the strong happiness when the clients acclaim the work at last. So, I believe that no one will affirm that being an architect is a boring position even though they only do design every day.Consequently, we have to clarify which reasons lead workers to be happy. How different the type of tasks is unlikely to simply determine how happy workers can be during their workday. If one type of task containing diverse challenges stimulates someone’s motivation, the people would attain likewise pleasure from the work.。