托福TPO48阅读Passage3原文文本+题目+答案解析
托福TPO48口语Task3阅读文本+听力文本+题目+满分范文
为了帮助大家高效备考托福，为大家带来托福TPO48口语Task3阅读文本+听力文本+题目+满分范文，希望对大家备考有所帮助。
托福TPO48口语Task3阅读文本： An Art Museum at the University Many universities have their own art museums, with collections of paintings and sculptures by well-known artists. I think our university should create a similar museum on our own campus. Such a museum would give our students an opportunity to learn to appreciate high-quality fine art. It would be a great way for us to see artworks that we might not have access to other wise. In order to pay for the museum, the university could write letters to alumni asking them to donate money to help build the museum. I’m sure many former students love art and would be glad to donate money to help the university build a museum here.SincerelyDiane Miller 托福TPO48口语Task3听力文本： Listen to two students discussing the letter. Woman：Did you see this letter? Man：Yeah. It's a nice idea, but it'll never happen. Woman：Why do you say that? Man：Well, first of all, you can get on a bus right here on campus and in half an hour, you are downtown at the county art museum. Woman：That's true. Man：And if you show you student ID card, it only costs like two bucks to get in. Woman：Yeah. In fact, on Mondays, students get in for free. Man：Right. And you can see some of the greatest art in the world there. For example, you know Rembrandt, the famous Dutch painter? Woman：Yeah. Man：Well, right now they're showing something like twenty of his paintings. Woman：Wow! Man：Yeah. And you know, it's true. We do have a lot of very generous alumni. But we're already asking them for help building a new student center and a new library. And those are both very expensive projects. Woman：Yeah. That's right. Man：So I don't think we can expect them to donate much money for anything else anytime soon, especially for something we don't really need. 托福TPO48口语Task3题目： The man expresses his opinion about the letter-writer’s proposal. Briefly summarize the proposal. Then state the man’s opinion and explain the reasons he gives for holding that opinion. 托福TPO48口语Task3满分范文： It is suggested by the student that the university should construct an art museum on campus for students to appreciate high-quality fine works, the capital of which alumni can be invited to make a contribution to. The man in the conversation does not agree with the proposal. First of all, it takes only half an hour to go by bus from campus to the downtown art museum where pictures from masters such as Rembrandt will be exhibited. For students, it is free on Mondays and charges as little as two bucks on other days. Secondly, although alumni are bounteous, they have already shouldered the responsibility of a new student center and a new library, the two costly projects. 以上是给大家整理的托福TPO48口语Task3阅读文本+听力文本+题目+满分范文，希望对你有所帮助!。
托福TPO3阅读Passage3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TPO3阅读Passage3原文文本+题目+答案解析，希望对大家备考有所帮助。
▉托福TPO3阅读Passage3原文文本： The Long-Term Stability of Ecosystems Plant communities assemble themselves flexibly, and their particular structure depends on the specific history of the area. Ecologists use the term “succession” to refer to the changes that happen in plant communities and ecosystems over time. The first community in a succession is called a pioneer community, while the long-lived community at the end of succession is called a climax community. Pioneer and successional plant communities are said to change over periods from 1 to 500 years. These changes—in plant numbers and the mix of species—are cumulative. Climax communities themselves change but over periods of time greater than about 500 years. An ecologist who studies a pond today may well find it relatively unchanged in a year’s time. Individual fish may be replaced, but the number of fish will tend to be the same from one year to the next. We can say that the properties of an ecosystem are more stable than the individual organisms that compose the ecosystem. At one time, ecologists believed that species diversity made ecosystems stable. They believed that the greater the diversity the more stable the ecosystem. Support for this idea came from the observation that long-lasting climax communities usually have more complex food webs and more species diversity than pioneer communities. Ecologists concluded that the apparent stability of climax ecosystems depended on their complexity. To take an extreme example, farmlands dominated by a single crop are so unstable that one year of bad weather or the invasion of a single pest can destroy the entire crop. In contrast, a complex climax community, such as a temperate forest, will tolerate considerable damage from weather to pests. The question of ecosystem stability is complicated, however. The first problem is that ecologists do not all agree what “stability” means. Stability can be defined as simply lack of change. In that case, the climax community would be considered the most stable, since, by definition, it changes the least over time. Alternatively, stability can be defined as the speed with which an ecosystem returns to a particular form following a major disturbance, such as a fire. This kind of stability is also called resilience. In that case, climax communities would be the most fragile and the least stable, since they can require hundreds of years to return to the climax state. Even the kind of stability defined as simple lack of change is not always associated with maximum diversity. At least in temperate zones, maximum diversity is often found in mid-successional stages, not in the climax community. Once a redwoodforest matures, for example, the kinds of species and the number of individuals growing on the forest floor are reduced. In general, diversity, by itself, does not ensure stability. Mathematical models of ecosystems likewise suggest that diversity does not guarantee ecosystem stability—just the opposite, in fact. A more complicated system is, in general, more likely than a simple system to break down.A fifteen-speed racing bicycle is more likely to break down than a child’s tricycle. Ecologists are especially interested to know what factors contribute to the resilience of communities because climax communities all over the world are being severely damaged or destroyed by human activities. The destruction caused by the volcanic explosion of Mount St. Helens, in the northwestern United States, for example, pales in comparison to the destruction caused by humans. We need to know what aspects of a community are most important to the community’s resistance to destruction, as well as its recovery. Many ecologists now think that the relative long-term stability of climax communities comes not from diversity but from the “patchiness” of the environment, an environment that varies from place to place supports more kinds of organisms than an environment that is uniform. A local population that goes extinct is quickly replaced by immigrants from an adjacent community. Even if the new population is of a different species, it can approximately fill the niche vacated by the extinct population and keep the food web intact. ▉托福TPO3阅读Passage3题目： Question 1 of 14 The word “particular ” in the passage is closest in meaning to A. natural. B. final. C. specific. D. complex. Question 2 of 14 According to paragraph 1, which of the following is NOT true of climax communities? A. They occur at the end of a succession..。
托福阅读tpo48-3 word版本-Climate and Urban Development
Climate and Urban DevelopmentFor more than a hundred years, it has been known that cities are generally warmer than surrounding rural areas. This region of city warmth, known as the urban heat island, can influence the concentration of air pollution. However, before we look at its influence, let's see how the heat island actually forms.The urban heat island is due to industrial and urban development. In rural areas, a large part of the incoming solar energy is used in evaporating water from vegetation and soil. In cities, where less vegetation and exposed soil exist, the majority of the Sun's energy is absorbed by urban structures and asphalt. Hence, during warm daylight hours, less evaporative cooling in cities allows surface temperatures to rise higher than in rural areas. The cause of the urban heat island is quite involved. Depending on the location, time of year, and time of day, any or all of the following differences between cities and their surroundings can be important: albedo (reflectivity of the surface), surface roughness, emissions of heat, emissions of moisture, and emissions of particles that affect net radiation and the growth of cloud droplets.The word "involved" in the passage is closest in meaning to∙uncertain∙complicated∙common∙clearParagraph 2 mentions all of the following as varying the importance of albedo and other factors EXCEPT∙seasons∙soil depth∙geographic location∙the time of dayAt night, the solar energy (stored as vast quantities of heat in city buildings and roads) is slowly released into the city air. Additional city heat is given off at night (and during the day) by vehicles and factories, as well as by industrial and domestic heating and cooling units. The release of heat energy is retarded by the tall vertical city walls that do not allow infrared radiation to escape as readily as does the relatively level surface of the surrounding countryside. The slow release of heat tends to keep nighttime city temperatures higher than those of the faster-cooling rural areas. Overall, the heat island is strongest at night when compensating sunlight is absent; during the winter, when nights are longer and there is more heat generated in the city; and when the region is dominated by a high-pressure area with light winds, clear skies,and less humid air. Over time, increasing urban heat islands affect climatological temperature records, producing artificial warming in climatic records taken in cities. This warming, therefore, must be accounted for in interpreting climate change over the past century.The word "retarded" in the passage is closest in meaning to∙disguised∙added to∙made possible∙slowed downSelect the TWO answer choices that describe ways mentioned in paragraphs 2 and 3 in which solar energy affects urban and rural areas. To receive credit, you must select TWO answers.∙Solar energy causes evaporation from vegetation and soil, producing a cooling effect.∙Solar energy stored as heat is lost quickly when tall city buildings guide hot air up and away from the surface.∙Solar energy increases the atmospheric pressure over open areas.∙Solar energy is stored up in buildings and roads and emitted as heat during the night. The constant outpouring of pollutants into the environment may influence the climate of the city. Certain particles reflect solar radiation, thereby reducing the sunlight that reaches the surface. Some particles serve as nuclei upon which water and ice form. Water vapor condenses onto these particles when the relative humidity is as low as 70 percent, forming haze that greatly reduces visibility. Moreover, the added nuclei increase the frequency of city fog.According to paragraph 4, how do pollutants reduce the distance it is possible to see?∙They increase the amount of sunlight that reaches the ground.∙They increase the relative humidity.∙They form particles that irritate the eye.∙They serve as nuclei around which water condenses.Studies suggest that precipitation may be greater in cities than in the surrounding countryside; this phenomenon may be due in part to the increased roughness of city terrain, brought on by large structures that cause surface air to slow and gradually converge. This piling up of air over the city then slowly rises,much like toothpaste does when its tube is squeezed. At the same time, city heat warms the surface air, making it more unstable, which enhances risings air motions, which, in turn, aids in forming clouds and thunderstorms. This process helps explain why both tend to be more frequent over cities.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.∙Until more studies are done, suggestions about the causes of precipitation in cities will focus on the roughness of terrain rather than on surface air and convergence.∙Certain phenomena of city landscapes, such as large structures, cause surface air to slow and converge, which brings a change in weather patterns to cities and rural areas.∙One reason why precipitation may be greater in cities than in the countryside is that large buildings that are found in cities cause surface air to slow and converge.∙Studies that focus on large structures, which are only partly responsible for the increased roughness of city terrain, are incomplete in their explanation of increased precipitation.Why does the author mention "toothpaste" being squeezed from a tube?∙To compare the movement of toothpaste from a tube to the movement of precipitation from clouds∙To suggest that the process of cloud formation is a simple, everyday experience∙To help the reader visualize the process of air movement over a city∙To contrast the slow rising of air currents with the rapid squeezing of toothpasteThe word "both" in the passage refers to∙piling up and warming of air∙clouds and thunderstorms∙warm surface air and rising air motions∙heat and instabilityOn clear still nights when the heat island is pronounced, a small thermal low-pressure area forms over the city. Sometimes a light breeze-called a country breeze-blows from the countryside into the city. If there are major industrial areas along the outskirts, pollutants are carried into the heart of town, where they tend to concentrate. Such an event is especially probable if vertical mixing and dispersion of pollutants are inhibited. Pollutants from urban areas may even affect the weather downwind from them.Look at the four squares [] that indicate where the following sentence could be added to the passage. Where would the sentence best fit?The resulting difference in atmosphere pressure between the city and the countryside can cause air to shift.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.Cities are generally warmer than the surrounding countryside, a phenomenon known as the urban heat island.∙∙∙Answer ChoicesA. In the countryside, much solar energy is used in evaporation, but in the citythis energy builds up as heat.B.Increased industrial and urban development has also increased averagelevels of humidity over the last century.C.Pollution from cars and factories helps increase the amounts of fog andprecipitation that occur in cities.D. The urban heat island is strongest in the summer, when the days are longand the sunlight is intense.E.Heat and air are trapped in the irregular spaces between buildings whichcreates the atmospheric conditions that result in storms and windsF.Country breezes blow pollutants put from the cities into the surroundingcountryside。
托福TPO8阅读Passage3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TPO8阅读Passage3原文文本+题目+答案解析，希望对大家备考有所帮助。
▉托福TPO8阅读Passage3原文文本： Running Water on Mars Photographic evidence suggests that liquid water once existed in great quantity on the surface of Mars. Two types of flow features are seen: runoff channels and outflow channels. Runoff channels are found in the southern highlands. These flow features are extensive systems—sometimes hundreds of kilometers in total length—of interconnecting, twisting channels that seem to mergeinto larger, wider channels. They bear a strong resemblance to river systems on Earth, and geologists think that they are dried-up beds of long-gone rivers that once carried rainfall on Mars from the mountains down into the valleys. Runoff channels on Mars speak of a time 4 billion years ago (the age of the Martian highlands), when the atmosphere was thicker, the surface warmer, and liquid water widespread. Outflow channels are probably relics of catastrophic flooding on Mars long ago. They appear only in equatorial regions and generally do not form extensive interconnected networks. Instead, they are probably the paths taken by huge volumes of water draining from the southern highlands into the northern plains. The onrushing water arising from these flash floods likely also formed the odd teardrop-shaped “islands” (resembling the miniature versions seen in the wet sand of our beaches at low tide) that have been found on the plains close to the ends of the outflow channels. Judging from the width and depth of the channels, the flow rates must have been truly enormous—perhaps as much as a hundred times greater than the 105 tons per second carried by the great Amazon river. Flooding shaped the outflow channels approximately 3 billion years ago, about the same times as the northern volcanic plains formed. Some scientists speculate that Mars may have enjoyed an extended early Period during which rivers, lakes, and perhaps even oceans adorned its surface. A 2003 Mars Global Surveyor image shows what mission specialists think may be a delta—a fan-shaped network of channels and sediments where a river once flowed into a larger body of water, in this case a lake filling a crater in the southern highlands. Other researchers go even further, suggesting that the data provide evidence for large open expenses of water on the early Martian surface. A computer-generated view of the Martian north polar region shows the extent of what may have been an ancient ocean covering much of the northern lowlands. The Hellas Basin, which measures some 3,000 kilometers across and has a floor that lies nearly 9 kilometers below the basin’s rim, is another candidate for an ancient Martian sea. These ideas remain controversial. Proponents point to features such as theterraced “beaches” shown in one image, which could conceivably have been left behind as a lake or ocean evaporated and the shoreline receded. But detractors maintain that the terraces could also have been created by geological activity, perhaps related to the geologic forces that depressed the Northern Hemisphere far below the level of the south, in which case they have nothing whatever to do with Martian water. Furthermore, Mars Global Surveyor data released in 2003 seem to indicate that the Martian surface contains too few carbonate rock layers—layers containing compounds of carbon and oxygen—that should have been formed in abundance in an ancient ocean. Their absence supports the picture of a cold, dry Mars that never experienced the extended mild period required to form lakes and oceans. However, more recent data imply that at least some parts of the planet did in fact experience long periods in the past during which liquid water existed on the surface. Aside from some small-scale gullies (channels) found since 2000, which are inconclusive, astronomers have no direct evidence for liquid water anywhere on the surface of Mars today, and the amount of water vapor in the Martian atmosphere is tiny. Yet even setting aside the unproven hints of ancient oceans, the extent of the outflow channels suggests that a huge total volume of water existed on Mars in the past. Where did all the water go? The answer may be that virtually all the water on Mars is now locked in the permafrost layer under the surface, with more contained in the planet’s polar caps. ▉托福TPO8阅读Passage3题目： Question 1 of 13 The word “merge ” in the passage is closest in meaning to A. expand B. separate C. straighten out D. combine Question 2 of 13 What does the discussion in paragraph 1 of runoff channels in the southern highlands suggest about Mars? A. The atmosphere of Mars was once thinner than it is today.。
tpo48
FEMALE EMPLOYEE: Hi, can I help you?MALE STUDENT: I hope so. My name's Mark Whitman, I'm--FEMALE EMPLOYEE: Don't I remember you from last year? You worked in uh…where was it, the art library?MALE STUDENT: Yeah. You're good. That was me. And I really enjoyed the work.FEMALE EMPLOYEE: Right. Yeah, your supervisor gave us some really great feedback at the end of the year. “Oh, he’s so organized, always on time,helpful...”MALE STUDENT: Really? Well, I'm glad. It was a good job.FEMALE EMPLOYEE: Well, we usually try to match students' jobs with their academic interests... MALE STUDENT: Yeah, I'm not exactly sure what career I'm headed for, but librarian is a possibility. It was a great experience to learn how it works and, and meet some people working in the field. But for this year...well, that’s what I wanted to ask about.FEMALE EMPLOYEE: Oh. How come you waited so long to come in? You know how fast campus jobs fill up. If you’d come in earlier, you could probably have gotten the library job again-- I mean, since you have the experience from last year, you don't need the training and all... but it's been filled now.MALE STUDENT: Yeah, I know. But I'd planned to get a job working at a restaurant off-campus this year.I really need to make more money than I did last year, and working as a waiter, there's always the tips. But…I've tried a ton of places and I haven't found anything. I know it’s really late, but well, uh, I was wondering… if maybe there was some job that hadn't been taken? Or maybe, umm, someone started a job and, ya know, had to drop it or something?FEMALE EMPLOYEE: Well, I doubt you'll find..MALE STUDENT: Could you, could you possibly check? I know it's a long shot but … My friend Suzanne, she takes photography classes in Harrison Hall. And, um, she sort of thought there might be an opening in the janitorial staff.FEMALE EMPLOYEE: Um, why does your friend, the photography student, think she has information about a janitorial staff opening? I'm pretty sure those jobs're filled. In fact, I remember taking lots of applications for them. Let me double check it online…MALE STUDENT: She said the whole studio arts building and especially the photo lab have been kind of, uh…sort of messy lately? I mean, she says there's, uh, chemicals and stuff left out and, ya know, it's like no one's been cleaning up. But that could just be, ya know, students using the lab after hours or something. Like, after it's been cleane.FEMALE EMPLOYEE: Hmm…hang on. There's…uh…there is um… an asterisk…uh, next to one of the job numbers here. There's a note. Let's see… Huh!… Your friend's right. Seems like one of the student janitors quit a couple weeks ago for some reason…. Well, whatever. It looks like this is your lucky day. MALE STUDENT: Wow! That is so great! So who's the contact person?FEMALE EMPLOYEE: Check with the janitorial office.MALE STUDENT: Fine. Thanks so much.MALE STUDENT: Hi, professor, I was hoping to ask you a few questions about the class you're teaching next semester, the course on Polish Drama? I was thinking of taking it.FEMALE PROFESSOR: Well, that's an upper-division course … You don’t look familiar to me. Are you a student in this department?MALE STUDENT: No, actually, I'm not.FEMALE PROFESSOR: OK. Have you had other classes in the Slavic Languages Department—here or somewhere else?MALE STUDENT: No, that's the thing…I was just wondering how good my Polish would hav e to be, whether the class is taught in Polish or not.FEMALE PROFESSOR: Well, you'd have to have some knowledge of it. By that level a lot of the students are quite fluent, plus there're some native speakers in the department. And we don't plan for it to happen, but it's pretty common for the discussions to kind of move in and out of English and Polish, and it can be difficult to follow, so … uh, how well do you speak Polish?MALE STUDENT: Not so great. It's just that my father's from there, so I'm interested in learning about, you know, Polish history, Polish culture. Plus, I'm studying drama—I'll probably major in it—I love plays. So I thought your course might be perfect.FEMALE PROFESSOR: Hmm, to be honest with you … you have to realize that we'll be watching videos of performances and maybe—if we can swing it—even watch a live performance, and those won't necessarily be in translation … Also, texts—texts are sometimes available in translation, but even then some references will be to the original. I’d hope you’d be fairly confident in reading.MALE STUDENT: To be honest, it sounds totally over my head.FEMALE PROFESSOR: You know what? I believe they'll be offering a survey course… on Polish literature … Let me check here …Yes, I thought it was being offered this time. Professor Jaworski's teaching it… Let's see… It covers the major works—you know, epic romantic poetry, the novels… And it does cover one or two plays.MALE STUDENT: And this is in English?FEMALE PROFESSOR: Yes, you'll be reading mostly English translations, and the discussions will be in English.MALE STUDENT: Hmmm. Novels and poetry…FEMALE PROFESSOR: They'll provide you with a great historical context for the plays, so when you do get to them, you’re going to really have a feel for the times they “lived” in, so to speak. Plus, this course might also give you the impetus to learn more Polish, you know, get it to the level where you'd be ready for the other class.MALE STUDENT: Hmmm …TPO 48 Lecture 1MALE PROFESSOR: So today we're going to continue our discussion of twentieth-century photography in the United States. Last time, we were talking about Alfred Stieglitz, and we saw that one of his goals was to introduce Americans to European art… Uh today we're going to look at another photographer from the early twentieth century—Uh yes, Jennifer. FEMALE STUDENT: Before we get to that, I had a question about Stieglitz …MALE PROFESSOR: Sure.FEMALE STUDENT: Well—Stieglitz was married to Georgia O'Keeffe, right?MALE PROFESSOR: That’s ri ght, Stieglitz was married to her, promoted her work, and actually took some amazing portraits of her when they were married. Uh for anyone who's not familiar with this, we're talking about the American painter Georgia O'Keeffe. FEMALE STUDENT: OK—well—I was wondering, Georgia O'Keeffe—y’know, I've heard her name so many times, and I've seen some of her work, but she's not mentioned in any of our reading about photographers from that time.MALE PROFESSOR: Uh—well—O'Keeffe was really more of a painter …FEMALE STUDENT: I thought she was a photographer too. I mean, I just saw one of her photographs, in a museum, the other day, I think it was called “Red Leaves on White,” or something like that.MALE PROFESSOR: Oh—right … Yes, Large Dark Red Leaves on White is the complete title. It’s a fairly well-known painting by O’Keeffe.FEMALE STUDENT: Oh, oh—OK—whoa, what was I thinking?! I guess I should’ve had a closer look.MALE PROFESSOR: No, no, that's a really good observation. I mean, chronologically, that would be impossible—when she did that painting, color film hadn't even been inventedyet—neither had the right technology to blow pictures up that big, to show that much detail. But that painting, and some of her other paintings, do reveal the-the influence of ph otography … like, she would “crop” her images—she, uh, she would make a “frame” around part of an image—say, just the very center—and then cut off certain parts—the parts outside that “frame”—to create the effect she wanted … the way a photographer does. A nd those paintings are “close-ups”—like you might see today—of a person—or a flower—in a photograph.Now those techniques were certainly around, and being used by photographers then—but just in photographs, which were smaller, not as big as what O'Keeffe was painting. Also, O'Keeffe studied under an artist named Arthur Wesley Dow. That’s Dow, D-O-W—who advocated focusing on simple, basic forms—like the lines of a flower and its petals—and he wanted forms to be isolated from their original settings.He-he believed that by doing that, an artist could reveal an object's—its—its essence. Mmm … Hm he’d do things like—like, have his students take a simple, ordinary form— like a leaf—and explore various ways of fitting all of it into a square—maybe bending it around to make the whole thing fit into the frame. Peter?MALE STUDENT: It sounds like maybe O’Keeffe borrowed most of her ideas—the stuff we might think of as being hers—she just got them from other people… she didn't really have a style of her own.MALE PROFESSOR: Well, virtually artists are influenced by other artists—by their predecessors … by their contemporaries—their teachers … Artists build on what other artists have done, but—if they're talented—they take it in some unique direction—to develop their own distinctive style.MALE PROFESSOR: O’Keeffe liked to create abstract interpretations of real objects— inthe painting Jennifer mentioned, Large Dark Red Leaves on White, in addition to exaggerating the size of the leaf, O'Keeffe juxtaposes it against a silver—or whitish—background, so that's more of an abstract setting for it. And so on.Now O'Keeffe wasn't the first artist to create an abstract interpretation of a real object, but she used that approach to express her experience of the objects she was pai nting … so she presented a vision that people hadn't seen before: It’s unique. It’s compelling.She didn't expect other people to experience the object the way she did—she knew they'd look at her painting and hang their own associations on it—which is true for artwork in general, I think; that's just the way the human brain works—uh, but at least they'd be taking a careful look at something they'd never really paid much attention to.TPO 48 Lecture 3FEMALE PROFESSOR: OK. Today I'd like to spend some time going into more detail about symbiosis. Symbiosis. What is it? Anyone?MALE STUDENT: I thought it's when two organisms are in a relationship that they both benefit from, well, at least that’s what I thought it was until I did the reading la st night. Now I'm kinda confused about it because the book used that definition to describe mutualism. Could you explain the difference?FEMALE PROFESSOR: Good. I was hoping that someone would bring that up. Sometimes scientists working in different fields use the term “symbiosis” to mean slightly different things, and it can get confusing, for example, when “symbiosis” is used as a synonym for “mutualism.” But there are quite a few of us out there who think there should be a clearer distinction made between the two.Ok, where to begin... Um, the original definition of symbiosis is pretty simple. It simply means living together. So, any close relationship between two organisms of different species would be considered a symbiotic relationship, including positive and negative relationships. Mutualism then is a kind of symbiosis, a specific type of symbiotic relationship where both organisms benefit somehow. So, your book is correct.Now, I want to make it clear that, um, the positive result from being in a mutualistic relationship doesn't have to be equal for both organisms. It's not a one-to-one ratio here. Is everyone with me so far? Symbiosis—general term, mutualism—a narrower, more specific kind of symbiosis.Now let's take a closer look at mutualistic relationships. I'll start off by describing a case of mutualism that involves a certain butterfly species found in South Africa and Australia. It’s a good example of how dependence on a mutualistic relationship can vary.OK, there's this butterfly family, and I'll spare you the fancy Latin name because it's not important for our purposes here. I'll call them coppers and blues, well…because most members of this family have blue or copper-colored wings. I think this is one of the most interesting cases of mutualism: These butterflies require the presence of ants to complete their life cycle—their interaction with ants is obligatory.So this is what happens. A female butterfly of these coppers and blues will lay eggs only on vegetation where there’re ants of a particular species. The butterflies can smell…well, ants leave behind pheromones—a special chemical signal. The butterfly recognizes the ants'pheromones on the plant…and then the newly hatched butterflies, the caterpillars, will feed on this plant after they hatch from the eggs. As the caterpillar gets a little older and finds shelter under nearby rocks or stones to protect itself from predators, it’s always attended or escorted by ants. And it always makes its way back to the host plant to feed, guided by the ants—the ant escort service—so to speak.Now why would the ants go through all this trouble? What's their benefit? Mary? FEMALE STUDENT: It's probably related to food …FEMALE PROFESSOR: Uh huh, you’re onto something …FEMALE STUDENT: OK. Ants feed on sweet stuff, right? So the caterpillar must have some kind of special access to honey, or sugars, or something like that. Maybe caterpillars produce honey somehow. On second thought…I'm probably way off.FEMALE PROFESSOR: You're pretty close, actually. Th e caterpillars have a “honey gland”—an organ that secretes an amino acid and carbohydrate liquid. The caterpillar secretes the liquid from the honey gland—rather large quantities—enough to feed several ants. But what makes this relationship obligatory for the caterpillar? Well, if the ants don’t feed regularly on the liquid from the caterpillar’s honey gland, the gland overloads and getsinfected. The infection will kill the caterpillar and it'll never reach its final stage of development—becoming a butterfly. John?MALE STUDENT: OK. I just wanna make sure I'm following here. The caterpillar needs the ants, or it won't make it to the stage where it can become a butterfly. And, the ants do this because they get an easy meal out of it, right? But the ants don't absolutely need the caterpillar for survival 'cuz they can get food from other places, right? So it's still called mutualism even though it seems like the caterpillar's getting way more out of it? [sudden realization] Oh. Wait. You said they don't have to equally benefit. Never mind. Sorry. FEMALE PROFESSOR: Yes, but there is a type of mutualism where the relationship is necessary for both organisms to survive. It's called obligatory mutualism. We'll talk about that in next class.TPO 48 Lecture 2MALE PROFESSOR: OK, we know the Earth's surface—the crust—is made up of tectonic plates … and that these huge slabs of rocky crust are slowly sliding over or under or past each other. And we said that most of the world's volcanoes occur at the boundaries of these tectonic plates, where you have hot, molten rock squeezing up through gaps between the plates.But some volcanoes occur … not at the edges, but in the middle of a continental or oceanic plate. The Hawaiian Islands for example, are thousands of kilometers away from any plate boundary. And yet, you have vast amounts of magma—molten rock or lava—flowing up through the Earth's crust … which means, of course, that volcanic activity there can't be explained simply by plate tectonics. So … how do we explain these volcanic anomalies... these exceptions to the general rule?Well, back in 1963, a geophysicist by the name of Wilson came up with the hot spot theory … to explain how this particular type of volcanic activity can occur—and can go on for ma ybe tens or even hundreds of millions of years. Wilson’s theory was that hot spots exist below tectonic plates and they’re the cause of these volcanoes. But what causes the hot spots?Hmmm. Well, the most popular theory that's been proposed is the plume hypothesis. According to this hypothesis, lumes—um, basically, columns of extremely hot magma—these plumes well up from deep inside the planet's interior—maybe even as deep as its core—and rise all the way up to melt through the Earth's crust.Imagine a burning candle. And imagine moving a sheet of heavy paper slowly over the flame of the candle—you’re gonna get a series of burned spots in the paper. Well that's just like what's happening with the Hawaiian Islands. But instead of a sheet of paper, you've got atectonic plate, and it's moving over this plume of intensely hot magma. And rather than a series of burned spots in the paper, you're getting a chain of volcanic islands... where the hot plume melts through the crust under the Pacific Ocean at one point after another—with active volcanoes on the younger islands that're now just above the plume, and the other islands … well, the farther away from the plume they are now, the older they are and the longer ago their volcanoes went dormant or extinct.Incidentally, volcanic islands may seem small, but the island known as the Big Island of Hawaii is one of the tallest topographic features on the planet—more than 5 kilometers from the seafloor to the ocean surface, and almost that much again … up to its highest peak. That's nearly 10 kilometers from ocean floor to the highest point on the island, which makes it taller even than Mount Everest. So … you can imagine the huge amounts of magma, or lava, that've flowed up to form even just this one island, much less the whole chain of islands.Now, the plume hypothesis provides a pretty elegant explanation for a volcanic anomaly like the Hawaiian Islands. But, while it's hypothetically attractive, there's very little direct evidence to support the theory because, so far, no one's been able to actually observe what's happening that far beneath the Earth's crust.Some studies've been done—seismographic, geochemical—where the data’s consistent with the model, but they aren't definitive proof. Even the model’s supporters aren’t comfortable claiming that it explains every volcanic anomaly …And—like any popular theory I suppose—it has some determined critics. These critics have put forth a number of alternative theories—all unproven so far—but one well-regarded theory is the crack hypothesis … which assumes that hot spots are created when a piece of the crust gets stretched thinner and thinner, and the resulting stress causes small cracks to open up at weak spots in the crust … and it's through these cracks that magma pushes up toform volcanoes.Proponents of the crack hypothesis consider this a widespread phenomenon … and believe that magma's not coming up from deep within the Earth's interior, but rather from just beneath the surface crust.This hypothesis is attractive because it fits with what we already know about plate tectonics … and it fits what we know about some secondary, smaller hot spots—but how well does it explain the Hawaiian Islands? Could a series of random cracks produce that same particular string of islands that sequence so neatly from old to young? You know, it worries me when a theory depends on coincidence to produce results.TPO 48 Lecture 4FEMALE PROFESSOR: We've been talking about the transformation... the industrialization of the United States economy in the nineteenth century. As the country shifted from an agricultural to an industrial base, political power shifted, too. Businesses became...a lot of power went, went, went, went from the government into, into the hands of business leaders.So, why did this happen? How did an elite group, a few business giants, how did they end up dominating, controlling a number of important national industries in the last quarter of the nineteenth century. How did they get to be so dominant? How did they figure out... how did they take advantage of the new industrialization of American society? Well consider the example of Andrew Carnegie and the steel industry.We've already discussed the development of a national network, a, a national system of railroads. Well, this growth created a tremendous demand for steel; a national railroad system needs a lot of railroad tracks, right? And Carnegie seized the opportunity. He built the world's most modern steel mill. And he came up with a system of business or-organization called vertical integration.Vertical integration just means that all... every single activity of a particular industry's processing is performed by a single company. In the case of the steel industry, this means the mining of iron ore, the transportation used to get ore from the mine to the mill, turning the ore into the steel, the manufacturing process, and sales. Carnegie controlled all of these; he practiced vertical integration on such a large scale that he practically owned the whole steel industry. This of course gave him a lot of political clout. Just a quick sketch, but you get theidea, right? Here’s another example—John D. Rockefeller.Rockefeller owned an oil refinery, but he wanted to expand his business. Since there was lots of competition in the industry, he thought the smart way to go about it would be to buy his competitors' businesses. But, at the time, it was illegal for one corporation to control another. So, what he did was, he created an organizational structure called a trust. A trust is—oh, well, I don't have to go into that now.What matters is that a trust created a single, central management team, and that team directed the activities of what otherwise still appeared to be independent companies. This new, ah, legal entity worked so well that at one point, Rockefeller controlled 90 percent of the country's oil refineries, which again gave him lots of political power.So you've got two different approaches to expanding a business, and both were quite effective. Of course, these weren't the only two examples; a number of big businesses run by powerful individuals developed across, oh, a wide range of industries, like railroads, food processing, electricity but what they all had in common was... the government let them operate pretty much how they wanted to.So why did they do that? Why did the government keep such a low profile and allow individuals to gain so much control of the industries? Well, obviously, they had the wealth and the power to influence political leaders.But also, the truth is that these industry leaders made a significant contribution. Their investments in technologies led to the development of many new production techniques, which strengthened the economy. And, many of them gave lots of money to charity; Andrew Carnegie was particularly admired for his generosity.But there was one thing in particular that gave them power, and that's . . . they were beneficiaries, probably the biggest beneficiaries of, of, of, uh, a theory, a dominant politicaltheory in the nineteenth century, something called laissez-faire doctrine. Laissez-faire roughly means “let it alone,” and that pretty much summarized the theory's philosophy. The idea was that government should leave business alone, allow it to operate unregulated. Legislatures weren't supposed to pass a lot of laws, or worry about regulating business practices. When people did challenge a company's business conduct, I mean, I mean in court cases, well, the few laws that did exist were usually interpreted in favor of business interests.But, over time, it started becoming increasingly obvious, and troubling to the public, that some of these big companies simply had too much control. There were criticisms that owners had too much opportunity to exploit workers, workers and consumers, because they could control prices and wages. And small business owners and small farmers couldn't compete.So there was bad press, bad publicity. Enough that the government eventually felt it had to do something. So it passed two key pieces of legislation. One law was designed to regulate the prices set by the railroads. Another made it illegal for trusts to be used to limit competition. Both were aimed squarely at reducing the exclusive control that existed in some industries.。
托福TPO40阅读Passage3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TPO40阅读Passage3原文文本+题目+答案解析，希望对大家备考有所帮助。
Amphibian Thermoregulation In contrast to mammals and birds,amphibians are unable to produce thermal energy through their metabolic activity,which would allow them to regulate their body temperature independent of the surrounding or ambient temperature.However,the idea that amphibians have no control whatsoever over their body temperature has been proven false because their body temperature does not always correspond to the surrounding temperature.While amphibians are poor thermoregulators,they do exercise control over their body temperature to a limited degree. Physiological adaptations can assist amphibians in colonizing habitats where extreme conditions prevail.The tolerance range in body temperature represents the range of temperatures within which a species can survive.One species of North American newt is still active when temperatures drop to-2°C while one South American frog feels comfortable even when temperatures rise to 41°C—the highest body temperature measured in a free-ranging amphibian.Recently it has been shown that some North American frog and toad species can survive up to five days with a body temperature of-6°C with approximately one-third of their body fluids frozen.The other tissues are protected because they contain the frost-protective agents glycerin or glucose Additionally,in many species the tolerance boundaries are flexible and can change as a result of acclimatization(long-term exposure to particular conditions). Frog species that remain exposed to the sun despite high diurnal(daytime)temperatures exhibit some fascinating modifications in the skin structure that function as morphological adaptations.Most amphibian skin is fully water permeable and is therefore not a barrier against evaporation or solar radiation.The African savanna frog Hyperolius viridiflavus stores guanine crystals in its skin,which enable it to better reflect solar radiation,thus providing protection against overheating.The tree frog Phyllomedusa sauvagei responds to evaporative losses with gland secretions that provide a greasy film over its entire body that helps prevent desiccation(dehydration). However,behavior is by far the most important factor in thermoregulation.The principal elements in behavioral thermoregulation are basking(heliothermy),heat exchange with substrates such as rock or earth(thigmothermy),and diurnal and annual avoidance behaviors,which include moving to shelter during the day for cooling and hibernating or estivating(reducing activity during cold or hot weather,respectively)Heliothermy is especially common among frogs and toads:it allows them to increase their body temperature by more than 10°C.The Andean toad Bufo spinulosus exposes itself immediately after sunrise on moist ground and attains its preferred body temperature by this means,long before either ground or air iscorrespondingly warmed.A positive side effect of this approach is that it accelerates the digestion of the prey consumed overnight,thus also accelerating growth.Thigmothermy is a behavior present in most amphibians,although pressing against the ground serves a dual purpose:heat absorption by conductivity and water absorption through the skin.The effect of thigmothermy is especially evident in the Andean toad during rainfall:its body temperature corresponds to the temperature of the warm earth and not to the much cooler air temperature. Avoidance behavior occurs whenever physiological and morphological adaptations are insufficient to maintain body temperature within the vital range.Nocturnal activity in amphibians with low tolerance for high ambient temperatures is a typical thermoregulatory behavior of avoidance.Seasonal avoidance behavior is extremely important in many amphibians.Species whose habitat lies in the temperate latitudes are confronted by lethal low temperatures in winter,while species dwelling in and and semi-and regions are exposed to long dry,hot periods in summer. In amphibians hibernation occurs in mud or deep holes away from frost.North of the Pyrenees Mountains,the natterjack toad offers a good example of hibernation,passing the winter dug deep into sandy ground.Conversely,natterjacks in southern Spain remain active during the mild winters common to the region and are instead forced into inactivity during the dry,hot summer season.Summer estivation also occurs by burrowing into the ground or hiding in cool,deep rock crevasses to avoid desiccation and lethal ambient temperature.Amphibians are therefore hardly at mercy of ambient temperature,since by means of the mechanisms described above they can more than exercise some control over their body temperature. paragraph 1 In contrast to mammals and birds,amphibians are unable to produce thermal energy through their metabolic activity,which would allow them to regulate their body temperature independent of the surrounding or ambient temperature.However,the idea that amphibians have no control whatsoever over their body temperature has been proven false because their body temperature does not always correspond to the surrounding temperature.While amphibians are poor thermoregulators,they do exercise control over their body temperature to a limited degree. 1.According to paragraph 1,what indicates that amphibians have some control over their body temperature? A.Amphibians can regulate their metabolic rates to generate energy. B.Amphibians use the same means of thermoregulation as mammals and birds do. C.The body temperature of amphibians sometimes differs from the temperature of。
PO48托福综合写作题目文本答案解析
PO48托福综合写作题目文本答案解析
在托福写作备考的过程时候，大家往往会把更多的精力放在托福独立写作的准备中。
但是，想要冲刺的托福写作的高分，综合写作也是我们必须要冲过的一个难关。
那么，在以下内容中，就为大家带来TPO48托福综合写作题目文本及答案解析，希望能为大家的备考带来帮助。
W1
综合写作
Question: Summarize the points made in the lecture, being sure to explain how they cast doubt on the specific methods proposed in the reading passage.
高分词汇：measure, decline, establish, pesticide, pragmatic, endanger, infection, antifungal, scale, object, reverse, trigger
话题：Biology 生物学
材料要点重现：lecture中教授的观点是三种组织青蛙减少的方法没有用。
第一方法，让靠近青蛙栖
息地的农民少喷杀虫剂，但对一些农民不公平。
第二方法，喷洒抗菌药防止青蛙脱水，但要对每一代每一只青蛙喷洒执行难度很大成本很高。
第三方法，让人类少用水来保护青蛙栖息地，但栖息地消失的真正原因是全球变暖。
范文：
点击查看完整解析：PO48托福综合写作题目文本答案解析。
2021年托福阅读PASSAGE 48 试题及答案
2021年托福阅读PASSAGE 48试题及答案PASSAGE 48According to sociologists, there are several different ways in which a person may become recognized as the leader of a social group in the United States. In the family, traditional cultural patterns confer leadership on one or both of the parents. In other cases, such as friendship groups, one or more persons may gradually emerge as leaders, although there is no formal process of selection. In larger groups, leaders are usually chosen formally through election or recruitment.Although leaders are often thought to be people with unusual personal ability, decades of research have failed to produce consistent evidence that there is any category of "natural leaders." It seems that there is no set of personal qualities that all leaders have in common; rather, virtually any person may be recognized as a leader if the person has qualities that meet the needs of that particular group. Furthermore, although it is commonly supposed that social groups have a single leader, research suggests that there are typically two different leadership roles that are held by different individuals. Instrumental leadership is leadership that emphasizes the completion of tasks by a social group. Group members look to instrumental leaders to "get things done." Expressive leadership, on the other hand, is leadership that emphasizes the collective well-being of a social group's members. Expressive leaders are less concerned with the overall goals of the group than with providing emotional support to group members and attempting to minimize tension and conflict among them. Group members expect expressive leaders to maintain stable relationships within the group and provide support to individual members.Instrumental leaders are likely to have a rather secondary relationship to other group members. They give orders and may discipline group members who inhibit attainment of the group's goals. Expressive leaders cultivate a more personal or primary relationship to others in the group. They offer sympathy when someone experiences difficulties or is subjected to discipline, are quick to lighten a serious moment with humor, and try to resolve issues that threaten to divide the group. As the differences in these two roles suggest, expressive leaders generally receive more personal affection from group members; instrumental leaders, if they are successful in promoting group goals, may enjoy a more distant respect.1. What does the passage mainly discuss?(A) The problems faced by leaders(B) How leadership differs in small and large groups(C) How social groups determine who will lead them(D) The role of leaders in social groups2. The passage mentions all of the following ways by which people can becomeleaders EXCEPT(A) recruitment(B) formal election process(C) specific leadership training(D) traditional cultural patterns3. In mentioning "natural leaders" in line 9, the author is making the point that(A) few people qualify as "natural leaders"(B) there is no proof that "natural leaders" exist(C) "natural leaders' are easily accepted by the members of a social group(D) "natural leaders" share a similar set of characteristics4. Which of the following statements about leadership can be inferred from paragraph 2?(A) A person who is an effective leader of a particular group may not be an effective leader in another group.(B) Few people succeed in sharing a leadership role with another person.(C) A person can best learn how to be an effective leader by studying research on leadership.(D) Most people desire to be leaders but can produce little evidence of their qualifications.5. The passage indicates that instrumental leaders generally focus on(A) ensuring harmonious relationships(B) sharing responsibility with group members(C) identifying new leaders(D) achieving a goal6. The word "collective" in line 17 is closest in meaning to(A) necessary(B) typical(C) group(D) particular7. The word "them" in line 19 refers to(A) expressive leaders(B) goals of the group(C) group members(D) tension and conflict8. A "secondary relationship" mentioned in line 22 between a leader and the members of a group could best be characterized as(A) distant(B) enthusiastic(C) unreliable(D) personal9. The word "resolve" in line 27 is closest in meaning to(A) avoid repeating(B) talk about(C) avoid thinking about(D) find a solution for10. Paragraphs 3 and 4 organize the discussion of leadership primarily in term of(A) examples that illustrate a problem(B) cause and effect analysis(C) narration of events(D) comparison and contrastANSWER KEYSPASSAGE 48 DCBAD CCADD。
托福TPO48综合写作阅读原文+听力原文+满分范文
为了帮助大家高效备考托福，为大家带来托福TPO48综合写作阅读原文+听力原文+满分范文，希望对大家备考有所帮助。
托福TPO48综合写作阅读原文文本： In recent years, many frog species around the world have declined in numbers or even gone extinct due to changes in their environment. These population declines and extinctions have serious consequences for the ecosystems in which frogs live; for example, frogs help play a role in protecting humans by eating disease-carrying insects. Several methods have been proposed to solve the problem of declining frog populations. First, frogs are being harmed by pesticides, which are chemicals used to prevent insects from damaging farm crops such as corn and sugarcane. Pesticides often spread from farmland into neighboring frog habitats. Once pesticides enter a frog’s body, they attack the nervous system, leading to severe breathing problems. If laws prohibited the farmers from using harmful pesticides near sensitive frog populations, it would significantly reduce the harm pesticides cause to frogs. A second major factor in frog population decline is a fungus that has spread around the world with deadly effect. The fungus causes thickening of the skin, and since frogs use their skin to absorb water, infected frogs die of dehydration. Recently, researchers have discovered several ways to treat or prevent infection, including antifungal medication and treatments that kill the fungus with heat. Those treatments, if applied on a large scale, would protect sensitive frog populations from infection. Third, in a great many cases, frog populations are in decline simply because their natural habitats are threatened. Since most frog species lay their eggs in water, they are dependent on water and wetland habitats. Many such habitats are threatened by human activities, including excessive water use or the draining of wetlands to make them suitable for development. If key water habitats such as lakes and marshes were better protected from excessive water use and development, many frog species would recover. 托福TPO48综合写作听力原文文本： None of the methods proposed in the reading offers a practical solution for slowing down the decline in frog populations. There are problems with each of the methods you read about. First, seriously reducing pesticides in agricultural areas with threatened frog populations is not economically practical or fair. Farmers rely on pesticides to decrease crop losses and stay competitive in the market. If farmers in areas that are close to endangered frog populations have to follow stricter regulations regarding pesticide use, then those farmers would be at a severe disadvantage compared to farmers in other areas. They would likely lose more crops and have a lower yield than competing farms. Second, the new treatments against the skin fungus you read about? Let me explain a couple of problems with this plan. The treatments must be applied individually to each frog. And so using them on a large scale is extremely difficult. It requires capturing and treating each individual frog in a population. Moreover, the treatments do not prevent the frogs from passing the fungus onto their offspring. So the treatments would have to be applied again and again to each new generation of frogs. So applying these treatments would be incredibly complicated and expensive. Third, while it's a good idea to protect lakes and marshes from excessive water use and development, that will not save frog populations. You see, water use and development are not the biggest threats to water and wetland habitats. The real threat is global warming. In recent decades, global warming has contributed to the disappearance of many water and wetland habitats, causing entire species to go extinct. Prohibiting humans from using water or building near frog habitats is unlikely to prevent the ongoing habitat changes caused by global warming. 托福TPO48综合写作满分范文： The lecturer argues against the three measures mentioned in the reading passage to solve the problem of declining frog populations. Firstly, the reading passage argues law should be established to prohibit the farmers from applying harmful pesticides near sensitive frog populations. The lecturer, however, argues that the first measure is not economically pragmatic or fair. Farmers who have to obey stricter regulations regarding pesticide use near endangered frog populations will be less competitive than farmers in other areas and have a lower yield. Regarding the second method of treating or preventing infection, including antifungal medication and heat treatments, the lecturer explains that it is extremely hard to capture each individual frog and apply these treatments on a large scale. Besides, the fungus cannot be stopped from passing onto the next generation, so the whole project will incredibly costly. Finally, the lecturer objects to the third proposal that human being should refrain from activities such as using excessive water or draining wetlands. She points out that the real threat to frog habitats is global warming which has contributed to the disappearance of many water and wetland habitats. Therefore, forbidding humans from using water or building near frog habitats is impossible to reverse the ongoing habitat losses triggered by global warming. 以上是给大家整理的托福TPO48综合写作阅读原文+听力原文+满分范文，希望对你有所帮助!。
tpo48三篇阅读原文译文题目答案译文背景知识
托福阅读tpo48全套解析阅读-1 (2)原文 (2)译文 (5)题目 (7)答案 (17)背景知识 (18)阅读-2 (19)原文 (19)译文 (23)题目 (25)答案 (36)背景知识 (37)阅读-3 (38)原文 (38)译文 (41)题目 (43)答案 (53)背景知识 (57)阅读-1原文Chinese Population Growth①Increases in population have usually been accompanied(indeed facilitated)by an increase in trade.In the Western experience, commerce provided the conditions that allowed industrialization to get started,which in turn led to growth in science,technology,industry, transport,communications,social change,and the like that we group under the broad term of“development.”However,the massive increase in population that in Europe was at first attributed to industrialization starting in the eighteenth century occurred also and at the same period in China,even though there was no comparable industrialization.②It is estimated that the Chinese population by1600was close to150 million.The transition between the Ming and Qing dynasties(the seventeenth century)may have seen a decline,but from1741to1851 the annual figures rose steadily and spectacularly,perhaps beginning with143million and ending with432million.If we accept these totals, we are confronted with a situation in which the Chinese population doubled in the50years from1790to1840.If,with greater caution,we assume lower totals in the early eighteenth century and only400million in1850,we still face a startling fact:something like a doubling of the vastChinese population in the century before Western contact,foreign trade, and industrialization could have had much effect.③To explain this sudden increase we cannot point to factors constant in Chinese society but must find conditions or a combination of factors that were newly effective in this period.Among these is the almost complete internal peace maintained under Manchu rule during the eighteenth century.There was also an increase in foreign trade through Guangzhou (southern China)and some improvement of transportation within the empire.Control of disease,like the checking of smallpox by variolation may have been important.But of most critical importance was the food supply.④Confronted with a multitude of unreliable figures,economists have compared the population records with the aggregate data for cultivated land area and grain production in the six centuries since1368.Assuming that China’s population in1400was about80million,the economist Dwight Perkins concludes that its growth to700million or more in the 1960s was made possible by a steady increase in the grain supply,which evidently grew five or six times between1400and1800and rose another50percent between1800and1965.This increase of food supply was due perhaps half to the increase of cultivated area,particularly by migration and settlement in the central and western provinces,and half to greater productivity—the farmers’success in raising more crops perunit of land.⑤This technological advance took many forms:one was the continual introduction from the south of earlier-ripening varieties of rice,which made possible double-cropping(the production of two harvests per year from one field).New crops such as corn(maize)and sweet potatoes as well as peanuts and tobacco were introduced from the Americas.Corn, for instance,can be grown on the dry soil and marginal hill land of North China,where it is used for food,fuel,and fodder and provides something like one-seventh of the food energy available in the area.The sweet potato,growing in sandy soil and providing more food energy per unit of land than other crops,became the main food of the poor in much of the South China rice area.⑥Productivity in agriculture was also improved by capital investments, first of all in irrigation.From1400to1900the total of irrigated land seems to have increased almost three times.There was also a gain in farm tools,draft animals,and fertilizer,to say nothing of the population growth itself,which increased half again as fast as cultivated land area and so increased the ratio of human hands available per unit of land. Thus the rising population was fed by a more intensive agriculture, applying more labor and fertilizer to the land.译文中国的人口增长①人口增长通常伴随着（事实上促进了）贸易的增加。
TPO-48 Reading 3 解析
Q1正确答案：B解析：involved：“卷入的；有关的；复杂的”；原文说城市热岛的成因非常involved，后文说由于位置、一年里的时间、一天里的时间等等多项因素，结合选项，只能选择B选项complicated“复杂的”；其余三个选项常见意分别为“不确定的”，“常见的”和“清楚的”。
Q2正确答案：B解析：根据题干定位原文段落的最后一句，time of year 对应A选项的seasons；C选项对应句中的location；D选项原文重现。
Q3正确答案：D解析：retarded：智力迟钝的；发展迟缓的。
在文中就是取第二个意思，表示缓慢的，对应D选项，从后文来看，下一句中的The slow release of heat 的slow已经有所指代。
Q4正确答案：D解析：根据题干定位原文“Certain particles…visibility.”粒子反射太阳辐射，减少到达地面的阳光（第2句，与A选项矛盾）；有些粒子是水和冰凝结成的核，当相对湿度低到70%，水蒸气也浓缩凝结在这些粒子上，形成雾霾。
结合选项，B选项曲解了原文意思，只是提到了相对湿度，没有说它们增加湿度；C选项没有提及；只能选择D选项。
Q5正确答案：A D解析：根据题干对solar energy 进行定位，P2开头第二句提到“In rural areas，a large part…vegetation and soil.”对应A选项；P3开头前两句“At night，… cooling units.”对应D选项；两个地方的定位句和两个选项都是同义表达，因此答案是A和D。
Q6正确答案：A解析：根据题干的interpretation of temperature 定位原文信息到本段的最后两句，最后两句说：城市热岛效应影响了气象学上的温度记录，导致了artificial warming （人为热岛效应的变暖）被记录在城市气候记录上；因此，理解过去一个世纪以来的气候变化必须要考虑这种变暖带来的影响。
TPO 47 Reading 3 解析
Passage 1Q 1正确答案：C解析：A对应原文中的a firm substratum。
B对应原文中的the seawater is not rendered too dark。
D对应原文中的the ocean water temperature is not less than 21°C。
只有C不是珊瑚生长的必要条件。
Q 2正确答案：C解析：原句意为，深约30~40米的平台比较是珊瑚生长的必要前提。
其中的prerequisite意为“前提，先决条件”，四个选项中，A意为“预防，防备”，B意为“准备，预备”，C意为“要求，必要条件”，D意为“成就”，只有C符合条件。
Q 3正确答案：A解析：A是对第1段中which help to build the reefs的同义转述，故为答案。
Q 4正确答案：B解析：原句意为，2000公里的珊瑚礁群被称为大堡礁，它构成了澳大利亚东北部地区的一个巨大的天然防波堤，也是目前地球上最大的珊瑚结构。
其中的complex意为“综合体，结合体”，四个选项中，A 意为“伸展，扩张”，B意为“系统”，C意为“地区”，D意为“多样化，类型”，只有B符合要求。
Q 5正确答案：A解析：第2段提到，达尔文将珊瑚分为三大类，他还发现，这些珊瑚之间存在逻辑和等级顺序上的联系。
A是对原文信息He recognized that … in a logical and gradational sequence.的综合概括，故为答案。
Q 6正确答案：B解析：原句意为，200多年以来，珊瑚吸引了科学家们的目光，其中1830年查尔斯·达尔文在乘坐贝格尔航行时对珊瑚礁的观察最为深入中肯。
句中的pertinent意为“相关的”，四个选项中，A意为“非凡的，特别的”，B意为“相关的”，C意为“聪明的”，D意为“著名的”，只有B符合条件。
Q 7正确答案：D解析：第2段提到，如果环礁湖宽而且深，且礁生长在离岸边一段距离的深水中，这种珊瑚礁就叫堡礁。
TPO 47 Reading 3 译文
珊瑚礁珊瑚礁生长的重要环境差不多仅限于热带区域。
它们一般见于海洋中的水温不低于21°C、基石坚定，并在海水没有因为过量的河流沉积物而显得太暗的环境中。
它们不会生长在深水之中，所以在海平面之下30米到40米之间要有一个平台，这是珊瑚礁生长的一个必要的前提条件。
珊瑚礁的物理结构主要是珊瑚的骨骼，也就是以浮游动物为食的肉食动物的尸骨。
然而，除了珊瑚以外，还有大量的藻类和一些钙质都对珊瑚礁的形成有帮助。
珊瑚礁的大小是不定的。
一些环礁体积非常之大——南太平洋马绍尔群岛的夸贾林环礁有120千米长，24千米宽，但大多数珊瑚礁都非常小，只能生长到水面以上几米。
被称为大堡礁的珊瑚礁群长达2000千米，在澳大利亚东北海岸形成了一个巨大的天然防波堤，是地球上迄今为止最大的珊瑚结构。
科学家研究珊瑚礁已经有近200年的时间，其中1830年查尔斯·达尔文在乘坐贝格尔航行时对珊瑚礁的观察最为深入中肯。
他识别出了三种主要的珊瑚礁：岸礁、堡礁和环礁；并且观察到珊瑚之间的排列是渐次有序、相互关联的。
岸礁生长于靠近大陆或岛屿的岸边，它的表面粗糙不平，沿着海岸在浅水区生长，外缘向海里倾斜。
岸礁和陆地之间有时会有一个小通道或泻湖。
如果环礁湖宽而且深，且礁生长在离岸边一段距离的深水中，这种珊瑚礁就叫堡礁。
环礁是一个环形或马蹄形礁，中间有一个泻湖。
达尔文的理论是：一种珊瑚礁类型可以演替为另一种类型，首先珊瑚会从一个正在下沉的平面上向上生长，岸礁就演变到堡礁阶段，由于中央岛全部沉入海里，只剩下珊瑚环绕的环礁湖或环礁留存下来。
在二十世纪50年代，达尔文提出这一理论很久之后，人们在太平洋的环礁上钻了一些深孔。
钻孔深达一千米，穿过珊瑚直到海底的岩石层，说明这些珊瑚已经生长了有数千万年了，因为地壳是以每一百万年15到51米的速度在下沉。
因此这说明达尔文的理论基本上是正确的。
有一些海底岛屿称为平顶山或海底山，在这些地方海底扩张带来的下沉速度太快，以至于珊瑚礁的生长速度跟不上。
托福TPO48口语｜题目+文本
小编下面给考生们带来了托福TPO48口语文本，六个task，希望大家有针对性的有计划的规划备考。
多做题，多积累、多研究，实现自我的不断提升，加油!向着梦想前进。
托福TPO48口语task1题目:Students study in a variety of ways. Explain how your study habits aredifferent from those of other students you know.托福TPO48口语task2题目:Some people like to shop in large grocery stores and department stores.Other people prefer to shop in small specialty stores. Which do you prefer?Explain why.托福TPO48口语Task3阅读+题目：An Art Museum at the University?Many universities have their own art museums, with collections of paintings and sculptures by well-known artists. I think our university should create a similar museum on our own campus. Such a museum would give our students an opportunity to learn to appreciate high-quality fine art. It would be a great way for us to see artworks that we might not have access to other wise. In order to pay for the museum, the university could write letters to alumni asking them to donate money to help build the museum. I’m sure many former students love art and would be glad to donate money to help the university build a museumhere.SincerelyDiane MillerQuestion: The man expresses his opinion about the letter-writer’s proposal.Briefly summarize the proposal. Then state the man’s opinion and explain the reasons he gives for holding that opinion.托福TPO48口语Task4阅读+题目：Optimal ForagingFood provides animals with the energy they need to survive. However,animals also lose energy in the process of obtaining, or foraging, for food. Therefore, in order to conserve energy, many animals behave in ways that minimize the energy they expend in the foraging process while at the same time maximizing their nutritional benefits. This energy-efficient approach to obtaining food is known as optimal foraging. The practice of optimal foraging allows animals to expend the least possible amount of energy while at the same time obtaining prey with high food value that will provide them with necessary nutrients.Question: Using the example from the lecture, explain the concept ofoptimal foraging.托福口语TPO48 Task5:State the solution you would recommendQuestion:Briefly summarize the problem the speakers are discussing. Then state which solution you would recommend. Explain the reasons for your recommendation.托福口语TPO48 Task6:Explain the two benefits of animal domestication Question:Using the example of goats from the lecture,explain the two benefits ofanimal domesticationfor early humans.以上就是小编为大家带来关于托福TPO口语资料供大家阅读参考，托福资料频道将第一。
托福TPO47阅读Passage3原文文本+题目+答案解析
托福TPO47阅读Passage3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TPO47阅读Passage3原文文本+题目+答案解析，希望对大家备考有所帮助。
Coral ReefsAn important environment that is more or less totally restricted to the intertropical zone is the coral reef.Coral reefs are found where the ocean water temperature is not less than 21°C,where there is a firm substratum,and where the seawater is not rendered too dark by excessive amounts of river-borne sediment.They will not grow in very deep water,so a platform within 30 to 40 meters of the surface is a necessary prerequisite for their development.Their physical structure is dominated by the skeletons of corals,which are carnivorous animals living off zooplankton.However,in addition to corals there are enormous quantities of algae,some calcareous,which help to build the reefs.The size of reefs is variable.Some atolls are very large—Kwajelein in the Marshall Islands of the South Pacific is 120 kilometers long and as much as 24 kilometers across-but most are very much smaller,and rise only a few meters above the water.The 2,000 kilometer complex of reefs known as the Great Barrier Reef,which forms a gigantic natural breakwater off the northeast coast of Australia,is by far the greatest coral structure on Earth.Coral reefs have fascinated scientists for almost 200 years,and some of the most pertinent observations of them were made in the 1830s by Charles Darwin on the voyage of the Beagle.He recognized that there were three major kinds:fringing reefs,barrier reefs,and atolls;and he saw that they were related to each other in a logical and gradational sequence.A fringing reefis one that lies close to the shore of some continent or island.Its surface forms an uneven and rather rough platform around the coast,about the level of low water,and its outer edge slopes downwards into the sea.Between the fringing reef and the land there is sometimes a small channel or lagoon.When the lagoon is wide and deep and the reef lies at some distance from the shore and rises from deep water it is called a barrier reef.An atoll is a reef in the form of a ring or horseshoe with a lagoon in the center.Darwin s theory was that the succession from one coral reef type to another could be achieved by the upward growth of coral from a sinking platform,and that there would be a progression from a fringing reef,through the barrier reef stage until,with the disappearance through subsidence(sinking)of the central island,only a reef-enclosed lagoon or atoll would survive.A long time after Darwin put forward this theory,some deep boreholes were drilled in the Pacific atolls in the 1950s.The drill holes passed through more than a thousand meters of coral before reaching the rock substratum of the ocean floor,and indicated that the coral had been growing upward for tens of millions of years as Earth's crust subsided at a rate of between 15 and 51 meters per million years.Darwin s theory was therefore proved basically correct.There are some submarine islands called guyots and seamounts,in which subsidence associated with sea-floor spreading has been too speedy for coral growth to keep up.Like mangrove swamps,coral reefs are extremely important habitats.Their diversity of coral genera is greatest in the warm waters of the Indian Ocean and the western Pacific.Indeed,they have been called the marine version of the tropical rain forest,rivaling their terrestrial counterparts in both richness ofspecies and biological productivity.They also have significance because they provide coastal protection,opportunities for recreation,and are potential sources of substances like medicinal drugs.At present they are coming under a variety of threats,of which two of the most important are dredging and the effects of increased siltation brought about by accelerated erosion from neighboring land areas.托福阅读TPO47Part3阅读题目：Passage 1An important environment that is more or less totally restricted to the intertropical zone is the coral reef.Coral reefs are found where the ocean water temperature is not less than 21°C,where there is a firm substratum,and where the seawater is not rendered too dark by excessive amounts of river-borne sediment.They will not grow in very deep water,so a platform within 30 to 40 meters of the surface is a necessary prerequisite for their development.Their physical structure is dominated by the skeletons of corals,which are carnivorous animals living off zooplankton.However,in addition to corals there are enormous quantities of algae,some calcareous,which help to build the reefs.The size of reefs is variable.Some atolls are very large—Kwajelein in the Marshall Islands of the South Pacific is 120 kilometers long and as much as 24 kilometers across-but most are very much smaller,and rise only a few meters above the water.The 2,000 kilometer complex of reefs known as the Great Barrier Reef,which forms a gigantic natural breakwater off the northeast coast of Australia,is by far the greatest coral structure on Earth.1.According to paragraph 1,all of the following are needed for the growth of coral reefs?A.a solid base to grow onB.exposure to lightC.the presence of river-borne sedimentD.ocean temperatures of 21°C or higher2.the word“prerequisite”in the passage is closest in meaning toA.precaution。
托福TPO40阅读Passage3原文文本+题目+答案解析
托福TPO40阅读Passage3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TPO40阅读Passage3原文文本+题目+答案解析，希望对大家备考有所帮助。
Amphibian ThermoregulationIn contrast to mammals and birds,amphibians are unable to produce thermal energy through their metabolic activity,which would allow them to regulate their body temperature independent of the surrounding or ambient temperature.However,the idea that amphibians have no control whatsoever over their body temperature has been proven false because their body temperature does not always correspond to the surrounding temperature.While amphibians are poor thermoregulators,they do exercise control over their body temperature to a limited degree.Physiological adaptations can assist amphibians in colonizing habitats where extreme conditions prevail.The tolerance range in body temperature represents the range of temperatures within which a species can survive.One species of North American newt is still active when temperatures drop to-2°C while one South American frog feels comfortable even when temperatures rise to 41°C—the highest body temperature measured in a free-ranging amphibian.Recently it has been shown that some North American frog and toad species can survive up to five days with a body temperature of-6°C with approximately one-third of their body fluids frozen.The other tissues are protected because they contain the frost-protective agents glycerin or glucose Additionally,in many species the tolerance boundaries are flexible and can change as a result of acclimatization(long-term exposure to particular conditions).Frog species that remain exposed to the sun despite high diurnal(daytime)temperatures exhibit some fascinating modifications in the skin structure that function as morphological adaptations.Most amphibian skin is fully water permeable and is therefore not a barrier against evaporation or solar radiation.The African savanna frog Hyperolius viridiflavus stores guanine crystals in its skin,which enable it to better reflect solar radiation,thus providing protection against overheating.The tree frog Phyllomedusa sauvagei responds to evaporative losses with gland secretions that provide a greasy film over its entire body that helps prevent desiccation(dehydration).However,behavior is by far the most important factor in thermoregulation.The principal elements in behavioral thermoregulation are basking(heliothermy),heat exchange with substrates such as rock or earth(thigmothermy),and diurnal and annual avoidance behaviors,which include moving to shelter during the day for cooling and hibernating or estivating(reducing activity during cold or hot weather,respectively)Heliothermy is especially common among frogs and toads:it allows them to increase their body temperature by mor e than 10°C.The Andean toad Bufo spinulosus exposes itself immediately after sunrise on moist ground and attains its preferred body temperature by this means,long before either ground or air iscorrespondingly warmed.A positive side effect of this approach is that it accelerates the digestion of the prey consumed overnight,thus also accelerating growth.Thigmothermy is a behavior present in most amphibians,although pressing against the ground serves a dual purpose:heat absorption by conductivity and water absorption through the skin.The effect of thigmothermy is especially evidentin the Andean toad during rainfall:its body temperature corresponds to the temperature of the warm earth and not to the much cooler air temperature.Avoidance behavior occurs whenever physiological and morphological adaptations are insufficient to maintain body temperature within the vital range.Nocturnal activity in amphibians with low tolerance for high ambient temperatures is a typical thermoregulatory behavior of avoidance.Seasonal avoidance behavior is extremely important in many amphibians.Species whose habitat lies in the temperate latitudes are confronted by lethal low temperatures in winter,while species dwelling in and and semi-and regions are exposed to long dry,hot periods in summer.In amphibians hibernation occurs in mud or deep holes away from frost.North of the Pyrenees Mountains,the natterjack toad offers a good example of hibernation,passing the winter dug deep into sandy ground.Conversely,natterjacks in southern Spain remain active during the mild winters common to the region and are instead forced into inactivity during the dry,hot summer season.Summer estivation also occurs by burrowing into the ground or hiding in cool,deep rock crevasses to avoid desiccation and lethal ambient temperature.Amphibians are therefore hardly at mercy of ambient temperature,since by means of the mechanisms described above they can more than exercise some control over their body temperature.paragraph 1In contrast to mammals and birds,amphibians are unable to produce thermal energy through their metabolic activity,which would allow them to regulate their body temperature independent of the surrounding or ambienttemperature.However,the idea that amphibians have no control whatsoever over their body temperature has been proven false because their body temperature does not always correspond to the surrounding temperature.While amphibians are poor thermoregulators,they do exercise control over their body temperature to a limited degree.1.According to paragraph 1,what indicates that amphibians have some control over their body temperature?A.Amphibians can regulate their metabolic rates to generate energy.B.Amphibians use the same means of thermoregulation as mammals and birds do.C.The body temperature of amphibians sometimes differs from the temperature of上一页下一页。
托福TPO8阅读Passage3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TPO8阅读Passage3原文文本+题目+答案解析，希望对大家备考有所帮助。
▉托福TPO8阅读Passage3原文文本： Running Water on Mars Photographic evidence suggests that liquid water once existed in great quantity on the surface of Mars. Two types of flow features are seen: runoff channels and outflow channels. Runoff channels are found in the southern highlands. These flow features are extensive systems—sometimes hundreds of kilometers in total length—of interconnecting, twisting channels that seem to mergeinto larger, wider channels. They bear a strong resemblance to river systems on Earth, and geologists think that they are dried-up beds of long-gone rivers that once carried rainfall on Mars from the mountains down into the valleys. Runoff channels on Mars speak of a time 4 billion years ago (the age of the Martian highlands), when the atmosphere was thicker, the surface warmer, and liquid water widespread. Outflow channels are probably relics of catastrophic flooding on Mars long ago. They appear only in equatorial regions and generally do not form extensive interconnected networks. Instead, they are probably the paths taken by huge volumes of water draining from the southern highlands into the northern plains. The onrushing water arising from these flash floods likely also formed the odd teardrop-shaped “islands” (resembling the miniature versions seen in the wet sand of our beaches at low tide) that have been found on the plains close to the ends of the outflow channels. Judging from the width and depth of the channels, the flow rates must have been truly enormous—perhaps as much as a hundred times greater than the 105 tons per second carried by the great Amazon river. Flooding shaped the outflow channels approximately 3 billion years ago, about the same times as the northern volcanic plains formed. Some scientists speculate that Mars may have enjoyed an extended early Period during which rivers, lakes, and perhaps even oceans adorned its surface. A 2003 Mars Global Surveyor image shows what mission specialists think may be a delta—a fan-shaped network of channels and sediments where a river once flowed into a larger body of water, in this case a lake filling a crater in the southern highlands. Other researchers go even further, suggesting that the data provide evidence for large open expenses of water on the early Martian surface. A computer-generated view of the Martian north polar region shows the extent of what may have been an ancient ocean covering much of the northern lowlands. The Hellas Basin, which measures some 3,000 kilometers across and has a floor that lies nearly 9 kilometers below the basin’s rim, is another candidate for an ancient Martian sea. These ideas remain controversial. Proponents point to features such as theterraced “beaches” shown in one image, which could conceivably have been left behind as a lake or ocean evaporated and the shoreline receded. But detractors maintain that the terraces could also have been created by geological activity, perhaps related to the geologic forces that depressed the Northern Hemisphere far below the level of the south, in which case they have nothing whatever to do with Martian water. Furthermore, Mars Global Surveyor data released in 2003 seem to indicate that the Martian surface contains too few carbonate rock layers—layers containing compounds of carbon and oxygen—that should have been formed in abundance in an ancient ocean. Their absence supports the picture of a cold, dry Mars that never experienced the extended mild period required to form lakes and oceans. However, more recent data imply that at least some parts of the planet did in fact experience long periods in the past during which liquid water existed on the surface. Aside from some small-scale gullies (channels) found since 2000, which are inconclusive, astronomers have no direct evidence for liquid water anywhere on the surface of Mars today, and the amount of water vapor in the Martian atmosphere is tiny. Yet even setting aside the unproven hints of ancient oceans, the extent of the outflow channels suggests that a huge total volume of water existed on Mars in the past. Where did all the water go? The answer may be that virtually all the water on Mars is now locked in the permafrost layer under the surface, with more contained in the planet’s polar caps. ▉托福TPO8阅读Passage3题目： Question 1 of 13 The word “merge ” in the passage is closest in meaning to A. expand B. separate C. straighten out D. combine Question 2 of 13 What does the discussion in paragraph 1 of runoff channels in the southern highlands suggest about Mars? A. The atmosphere of Mars was once thinner than it is today. B. Large amounts of rain once fell on parts of Mars. C. The river systems of Mars were once more extensive than Earth’s. D. The rivers of Mars began to dry up about 4 billion years ago. Question 3 of 13 The word “relics ” in the passage is closest in meaning to A. remains B. sites C. requirements D. sources Question 4 of 13 The word “miniature ” in the passage is closest in meaning to A. temporary B. small C. multiple D. familiar Question 5 of 13 In paragraph 2, why does the author include the information that 105 tons of water flow through the Amazon river per second? A. To emphasize the great size of the volume of water that seems to have flowed through Mars’ outflow channels B. To indicate data used by scientists to estimate how long ago Mars’ outflow channels were formed C. To argue that flash floods on Mars may have been powerful enough to cause tear-shaped “islands” to form D. To argue that the force of flood waters on Mars was powerful enough to shape the northern volcanic plains Question 6 of 13 According to paragraph 2, all of the following are true of the outflow channels on Mars EXCEPT: A. They formed at around the same time that volcanic activity was occurring on the northern plains. B. They are found only on certain parts of the Martian surface. C. They sometimes empty onto what appear to have once been the wet sands of tidal beaches. D. They are thought to have carried water northward from the equatorial regions. Question 7 of 13 All of the following questions about geological features on Mars are answered in paragraph 3 EXCEPT: A. What are some regions of Mars that may have once been covered with an ocean? B. Where do mission scientists believe that the river forming the delta emptied? C. Approximately how many craters on Mars do mission scientists believe may once have been lakes filled with water? D. During what period of Mars’ history do some scientists think it may have had large bodies of water? Question 8 of 13 According to paragraph 3, images of Mars’ surface have been interpreted as support for the idea that A. the polar regions of Mars were once more extensive than they are now B. a large part of the northern lowlands may once have been under water C. deltas were once a common feature of the Martian landscape D. the shape of the Hellas Basin has changed considerably over time Question 9 of 13 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. But detractors argue that geological activity may be responsible for the water associated with the terraces. B. But detractors argue that the terraces may have been formed by geological activity rather than by the presence of water. C. But detractors argue that the terraces may be related to geological forces in the Northern Hemisphere of Mars, rather than to Martian water in the south. D. But detractors argue that geological forces depressed the Northern Hemisphere so far below the level of the south that the terraces could not have been formed by water. Question 10 of 13 According to paragraph 4, what do the 2003 Global Surveyor data suggest about Mars? A. Ancient oceans on Mars contained only small amounts of carbon. B. The climate of Mars may not have been suitable for the formation of large bodies of water. C. Liquid water may have existed on some parts of Mars’ surface for long periods of time. D. The ancient oceans that formed on Mars dried up during periods of cold, dry weather. Question 11 of 13 The word “hints ” in the passage is closest in meaning to A. clues B. features C. arguments D. effects Question 12 of 13 Look at the four squares [■] that indicate where the following sentence could be added to the passage. Where would the sentence best fit? These landscape features differ from runoff channels in a number of ways.. Question 13 of 13 Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points. There is much debate concerning whether Mars once had water. A.Mars’ runoff and outflow channels are large-scale, distinctive features that suggest that large quantities of liquid water once flowed on Mars. B.Although some researchers claim that Mars may once have had oceans, others dispute this, pointing to an absence of evidence or offering alternative interpretations of evidence. C.Various types of images have been used to demonstrate that most of Martian surface contains evidence of flowing water. D.The runoff and outflow channels of Mars apparently carried a higher volume of water and formed more extensive networks than do Earth’s river systems. E.There is very little evidence of liquid water on Mars today, and it is assumed that all the water that once existed on the planet is frozen beneath its surface. F.While numerous gullies have been discovered on Mars since 2000, many astronomers dismiss them as evidence that Mars once had liquid water. ▉托福TPO8阅读Passage3答案解析： Question 1 of 13 正确答案：D 题目解析： merge: 合并。
托福阅读真题
托福阅读真题托福阅读真题Passage 1Artisans in Sixteenth-Century Europe(重复20150110考题) 文章解析文章分段概括：第一段，欧洲工匠几个世纪以来运作于小的独立的工业中，之后进化的经济系统（向现代资本主义）开始腐蚀欧洲稳定和繁荣位置。
什么导致了工匠的减少？一共两句话，第一句是长难句（此处句子简化题，抽取句子主干信息即可得到答案）。
第二段，几个世纪之后技术的革新花费了工匠更多的钱（细节题）。
举例，铁的生产需要的特殊设备。
因此，设备需要的资金高涨了。
（besides词汇题）第三段，然而原材料组成了工匠的主要花费。
silk weaver举例展开（修辞题）。
因此，便宜和足够的材料成为独立生产商的主要关注（preoccupation词汇题），用当地的材料可以避免依赖于供应商（细节题）。
当地材料的损失就会对工匠来说非常糟糕。
第四段，对于生产很重要的信用（credit）却容易对工匠产生额外的伤害。
产品价格的落后，coupled with（词汇题）税的增加让很多工匠难以还贷。
手工艺品需求的降低让工匠欠债更多，最后战事打断了原材料的供应和市场。
（否定事实信息题）。
第五段，工匠的独立（autonomy词汇题）也是很危险的。
会导致他们进入市场更加困难。
区域市场的消失会让weavers需要忍受大城市中间人（细节题）。
同样，（第二个例子）在Wiltshire南部的独立生产商也遇到的相似情况。
第六段，城市工匠惧怕乡村工业的发展。
因为会减少原材料的供应，提升产品价格。
乡村的地理位置让他们生存花费、赋税、工资较低，通常享受simplified processes。
随着竞争加剧，这些优势成为主要关注（否定事实信息题）。
解析：此篇文章难度中等，段落展开方式比较清晰，个别题目属于技巧性很强的题型。
词汇题整体偏简单。
其中开篇为一个几乎占据整个段落的句子简化题目，很多同学看到第一题这个长难句之后当时就被震惊了。
托福阅读真题第48篇TheCom...
托福阅读真题第48篇TheCom...美国国父托马斯·杰斐逊认为，农民是美国民主的基础。
为了执行他的民主计划，杰斐逊提出了美国矩形土地调查——俗称网格。
根据该计划，测量员首先被派往俄亥俄州东部，指示将土地划分为六英里见方的盒子。
然后他们被指示将这些较大的盒子分成较小的盒子，一英里见方，再分成四分之一部分，每个面积为160 英亩，被认为是适合单个农场的大小。
1785 年，国会通过了网格成为法律，从那时起，同样的棋盘图案在西方被蚀刻——这是世界历史上使景观合理化的最深远的尝试之一。
网格是一种文化的外在表达，不仅与民主结合，而且与市场和交换结合。
它将帮助该国迅速定居，将数百万美国人变成独立的土地所有者，同时将土地本身——其不同的地形、土壤和水条件——变成一种商品，一套统一的盒子很容易买到并出售。
但电网只是西方农田商业化的第一步。
一旦农民购买了土地，他们就需要耕种现有的植被。
在几千年前冰川留下的富含有机物的深厚土壤上茁壮成长的草最初是一个挑战。
事实证明，带有铁边的木犁几乎毫无用处。
钢犁的发展和传播——由1837 年由llinois 铁匠约翰迪尔发明——使耕作成功。
代替原生植被，农民种植玉米和小麦，驯化在单一文化环境中生长最好的草种，即在田地中自行生长。
这些作物往往生长迅速，将碳水化合物储存在种子中。
由于面包是美国人饮食的主要组成部分，小麦最终将成为西方的主要经济作物。
世界上一些英亩和英亩的土地'在定居初期，农民种植了多种谷物，包括小麦、玉米、燕麦、黑麦和大麦。
然而，随着商业农业在铁路运输改善的帮助下迅速发展，农民越来越专业化。
大部分谷物最终流向了东北部，到1840 年代，那里的人口增长已经超过了当地农业经济的供应能力。
实际上，西方过剩的土地财富为更远东的工业发展提供了保障。
The railroads not only delivered the products of the rich soils of the Western grasslands into the stomachs of Easterners, theyalso changed the meaning of the crops themselves. With waterborne transportation, farmers put their grain into sacks so they could easily be loaded into the irregularly shaped holds of steamboats. The advent of the railroads and steam-powered grain elevators (first developed in 1842) spurred farmers to eliminate the sack altogether. Now grain would move like a stream of water, making its journey to market with the aid of a mechanical device that loaded all the wheat from a particular area into one large grain car. Sacks had preserved the identity of each load of grain. With the new technology, however, grain from different farms was mixed together and sorted by grade. The Chicago Board of Trade (established in 1 848) divided wheat into three categories- spring, white winter, and red winter- -applying quality standards to each type. Wheat was turned into an abstract commodity, with ownership over the grain diverging from the physical product itself. By the 1860s, a futures market in grain had even emerged in Chicago. It was now possible to enter into a contract to purchase or sell grain at a particular price. What was being marketed here was not the physical grain itself so much as an abstraction, the right to trade something that may not even have been grown yet.1.美国国父托马斯·杰斐逊认为，农民是美国民主的基础。
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为了帮助大家高效备考托福，为大家带来托福TPO48阅读Passage3原文文本+题目+答案解析，希望对大家备考有所帮助。
Climate and Urban Development For more than a hundred years,it has been known that cities are generally warmer than surrounding rural areas.This region of city warmth,known as the urban heat island,can influence the concentration of air pollution.However,before we look at its influence,let’s see how the heat island actually forms. The urban heat island is due to industrial and urban development.In rural areas,a large part of the incoming solar energy is used in evaporating water from vegetation and soil.In cities,where less vegetation and exposed soil exist,the majority of the Sun’s energy is absorbed by urban structures and asphalt.Hence,during warm daylight hours,less evaporative cooling in cities allows surface temperatures to rise higher than in rural areas.The cause of the urban heat island is quite involved.Depending on the location,time of year,and time of day,any or all of the following differences between cities and their surroundings can be important:albedo(reflectivity of the surface),surface roughness,emissions of heat,emissions of moisture,and emissions of particles that affect net radiation and the growth of cloud droplets. At night,the solar energy(stored as vast quantities of heat in city buildings and roads)is slowly released into the city air.Additional city heat is given off at night(and during the day)by vehicles and factories,as well as by industrial and domestic heating and cooling units.The release of heat energy is retarded by the tall vertical city walls that do not allow infrared radiation to escape as readily as does the relatively level surface of the surrounding countryside.The slow release of heat tends to keep nighttime city temperatures higher than those of the faster-cooling rural areas.Overall,the heat island is strongest(1)at night when compensating sunlight is absent;(2)during the winter,when nights are longer and there is more heat generated in the city;and(3)when the region is dominated by a high-pressure area with light winds,clear skies,and less humid air.Over time,increasing urban heat islands affect climatological temperature records,producing artificial warming in climatic records taken in cities.This warming,therefore,must be accounted for in interpreting climate change over the past century. The constant outpouring of pollutants into the environment may influence the climate of the city.Certain particles reflect solar radiation,thereby reducing the sunlight that reaches the surface.Some particles serve as nuclei upon which water and ice form.Water vapor condenses onto these particles when the relative humidity is as low as 70 percent,forming haze that greatly reduces visibility.Moreover,the added nuclei increase the frequency of city fog. Studies suggest that precipitation may be greater in cities than in the surrounding countryside;this phenomenon may be due in part to the increased roughness of city terrain,brought on by large structures that cause surface air to slow and gradually converge.This piling up of air over the city then slowly rises,much like toothpaste does when its tube is squeezed.At the same time,city heat warms the surface air,making it more unstable,which enhances risings air motions,which,in turn,aids in forming clouds and thunderstorms.This process helps explain why both tend to be more frequent over cities. On clear still nights when the heat island is pronounced,a small thermal low-pressure area forms over the city.Sometimes a light breeze—called a country breeze—blows from the countryside into the city.If there are major industrial areas along the outskirts,pollutants are carried into the heat of town,where they tend to concentrate.Such an event is especially probable if vertical mixing and dispersion of pollutants are inhibited.Pollutants from urban areas may even affect the weather downwind from them. Paragraph 2 The urban heat island is due to industrial and urban development.In rural areas,a large part of the incoming solar energy is used in evaporating water from vegetation and soil.In cities,where less vegetation and exposed soil exist,the majority of the Sun’s energy is absorbed by urban structures and asphalt.Hence,during warm daylight hours,less evaporative cooling in cities allows surface temperatures to rise higher than in rural areas.The cause of the urban heat island is quite involved.Depending on the location,time of year,and time of day,any or all of the following differences between cities and their surroundings can be important:albedo(reflectivity of the surface),surface roughness,emissions of heat,emissions of moisture,and emissions of particles that affect net radiation and the growth of cloud droplets. 1.The word“involved”in the passage is closest in meaning to A.uncertain plicated mon D.clear 2.Paragraph 2 mentions all of the following as varying the importance of albedo and other factors EXCEPT。