TPO48托福综合口语题目文本及答案解析

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。

为了帮助大家高效备考托福，为大家带来托福TPO48口语Task5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Task5听力文本： Listen to a conversation between two students. Man：Hey. Cindy. You look happy. Making plans for the summer vacation? Woman：I'm just glad the semester is finally over. I just finished my final exam, so I'm taking off for summer vacation tomorrow. Aren't you? Man：I wish. Woman：What do you mean? Man：I have to rewrite the lab report for my biology class. I guess I did it all wrong. So the professor's making me rewrite it before he'll submit a final grade. Woman：I guess that's better than if he just gave you a bad grade on it, right? Man：I guess so. But I was planning on leaving town tomorrow too, and now I'm not sure I can. I spoke with the professor and he gave me two options. I can either turn in the revised report in one week and get my grade, or he said I can wait, you know, taking incomplete in the class and submit the paper next semester in the fall. Woman：So are you going to stay around to revise the report? Man：I could. I'd get the grade for the class on time and I wouldn't have to think about it anymore. But there's a family reunion this weekend. I was really looking forward to it. If I stay around to revise the report, I'll miss the reunion. Woman：Well, maybe you should take your time and work on the report over the summer. You can submit it when you return in the fall semester and get your grade then. Man：That would be fine, but what if I need materials from the library to revise the report? I don't know if I'll be able to find the materials at the library at home. Woman：Hmm... 托福TPO48口语Task5题目： Briefly summarize the problem the speakers are discussing. Then state whichsolution you would recommend. Explain the reasons for your recommendation. 托福TPO48口语Task5满分范文： The man is going to enjoy his summer vacation and have a family reunion this weekend. The problem is that he is required by the professor to rewrite the lab report for biology class before having a final grade. To solve the problem, the man can rewrite the report either on weekends or during the summer holiday. I prefer the second solution. I believe a qualified report requires more than a weekend to prepare, organize and complete. The shortcoming of lack of material at home can be overcome by borrowing books ahead of time in library. On the other hand, dashing off the report will lose the opportunity of family reunion and ruin the chance of a better score. 以上是给大家整理的托福TPO48口语Task5听力文本+题目+满分范文，希望对你有所帮助!。

为了帮助大家高效备考托福，为大家带来托福TPO48口语Task4阅读文本+听力文本+题目+满分范文，希望对大家备考有所帮助。

托福TPO48口语Task4阅读文本： Optimal Foraging Food 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. 托福TPO48口语Task4听力文本： Now listen to part of a lecture from a biology class. All right. So I've got a good example of this. There's a bird, a species of crow, that lives near the water and it feeds on a type of shellfish that has a hard outer shell. In order to eat the shellfish, the bird has to crack open its hard shell. So when this bird feeds, what it does is: it dives down out of the air into shallow water, grabs a shellfish in its mouth, then carries the shellfish up in the air. It then drops the shellfish, lets it fall onto the rocks below. When the shellfish hits the rocks, its shell cracks and splits open and the bird can eat it. Now, this bird, this crow, doesn't just swoop down, grab the first shellfish it sees and then fly up to any height and let it fall. Instead, it does two things. First, it carefully selects only the biggest shellfish. That means it's going to get the biggest possible meal for its efforts. Okay? Second, it carries the shellfish up to a specific height, about five meters, and drops it from there. If the bird dropped the shellfish from a lower height, it would have to pick it p and drop it too many times in order to break the shell. On the other hand, if the bird carried the shellfish up to a higher altitude, an altitude higher than it's necessary to crack the shell, it would be wasting energy. So this bird expends just the right amount of energy - no more no less - that it needs to obtain just the right kind of food. 托福TPO48口语Task4题目： Using the example from the lecture, explain the concept of optimal foraging. 托福TPO48口语Task4满分范文： The reading passage introduces a term called “Optimal Foraging”, which means the energy-efficient approach to gaining food by maximizing food nutrition and minimizing foraging energies. The lecturer further illustrates this term by using the example of a species of crow. Firstly, this bird will dive down into shallow water and choose the biggest shellfish rather than grab the first shellfish it sees so that its efforts will yield greatest harvest. Second, the crow drops the shellfish from about five meters in the air to crack open the shell by the rock below. The height won’t be too little to break the shell at one time and won’t be too much to waste the flying energy. 以上是给大家整理的托福TPO48口语Task4阅读文本+听力文本+题目+满分范文，希望对你有所帮助!。

正确答案：A解析：typically在字典中的第一个意思为：used to say that something usually happens in the way that you are stating. 表示“通常地，一般地”；traditionally 在文中表示“习俗的，惯例的”，只有A选项的typically 能够和它同义表达。

Q2正确答案：C解析：C选项对应原文第1句的“equally sharp teeth farther back in their jaws”；A 和B选项和本段最后1句信息矛盾；D选项的flat teeth这个信息和本段提到的有flat teeth的动物不是同一类，cows，horses等这些有flat teeth，紧接着下一句说unlike…teeth of carnivores，可见carnivores 是没有flat teeth的。

Q3正确答案：A解析：题目问的是作者把the teeth of cows, horses, rabbits, and mice比作grindstone 的目的是为了解释什么。

根据题干回归此段最后两句，在最后一句说到，不像肉食动物（carnivores），这些动物的牙齿是为了在消化之前碾磨和撕碎植物物质的（grind and shred plant material before digestion）。

用unlike部分作对比，强调后半句的内容，对应选项A。

Q4正确答案：B解析：把高亮文本句子结构精简，就是：The jaw joint of carnivores takes the advantage of same level of tooth row to close speedily and force upper teeth to occlude against the lower teeth precisely. 意思就是食肉动物利用了颌关节和牙齿同一高度的优势快速地闭合，也让上牙和下牙严密地咬合。

为了帮助大家高效备考托福，为大家带来托福TPO48口语Task2题目+满分范文，希望对大家备考有所帮助。

托福TPO48独立口语Task2题目：
Some people like to shop in large grocery stores and department stores. Other people prefer to shop in small specialty stores or shops. Which do you prefer? Explain why.
托福TPO48独立口语Task2满分范文：
I favor department stores more than those small specialty stores. One reason is that anything I want can be purchased from large grocery stores, so it is an ideal place for me to buy dresses, tops, shorts, bags and shoes at the same time. Another reason is that other entertainment facilities can also be offered by large grocery stores. When I get bored and tired, my parents or friends can go to café or restaurant and treat ourselves with a movie afterwards.
以上是给大家整理的托福TPO48口语Task2题目+满分范文，希望对你有所帮助!。

Q1正确答案：C解析：高亮文本的意思是：从西方社会的经验来看，商业为工业化提供发展条件，而工业化也反而让科学、技术、工业、交通、交流、社会变化和一切我们归纳为“发展”这个术语下的其他层面得以进步发展。

句子结构比较简单，就是说商业和工业让西方社会的许多方面得到发展。

原文中的commerce和题目选项中的trade是同义表达，trade也在第一句中提到了，C选项为正确答案。

A和B选项错误理解了development这个单词在句中的地位，D选项中的social change不对。

Q2正确答案：B解析：单词所在定位句的意思是：但是在欧洲，大规模的人口增长首先是归因于在18世纪开始的工业化发展，同期中国人口也在大规模增长，即便那时中国没有与之可比拟的工业化发展。

B选项的credit 取“归因于，把…归功于”的意思。

从前后文来看，这个单词只能取一个含有表原因意思的词来表达前后文的因果关系。

Q3正确答案：D解析：定位原文：“The transition…”明清过渡时期（也就是17世纪），中国人口数量可能有所下降（may have seen a decline），但是从1741到1851年年间，每年都在稳定和显著的增长。

后面接着说无论我们是否真的认可这些数据的真实性（if we accept…/If, with greater caution…），的确人口都翻倍增长了，在与西方外交，国外贸易和工业化之前，像中国人口翻倍增长的某些因素本应该对社会产生很大的影响的（像西方社会），但是实际却没有（could have done结构）。

也就是说基于前文讨论和人口增长的相关条件和影响，中国的人口增长情况却是讨论的特例，它缺少通常和人口增长相关的条件。

C选项错在说是基于previous centuries 的人口持续增长的基础上持续的，而17世纪明清两朝过渡时，人口数量可能是下降的。

Q4正确答案：B解析：段落中说从1741到1851期间，人后从最开始的143 million 到最后的432 million，保守估计，最后也有400 million。

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.。

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托福TPO48口语Task6听力文本： Listen to part of a lecture in a business class. Okay. So we have been discussing how companies use advertising to help sell their products. Now although advertisements can benefit companies, there are people who are critical of advertising because of certain environmental problems it can cause. So let's talk about two ways advertising can be seen to negatively affect the environment. One way is by wasting natural resources, like trees, by advertising to consumers who do not have a need for the product or service. The advertisement is irrelevant or useless for them. For instance, a piece of mail I got advertising a kitchen renovation service. A whole big booklet, lots of paper, about different ways to remodel your kitchen: changing the floors, adding new cupboards or appliances, but this was all a lot of wasted paper, wasted trees because I don't even own my place.I rent an apartment. So a kitchen renovation service is irrelevant to me. I can't use it. And I'm sure that booklet was mailed to lots of other people who also rent and who just threw the booklet into trash because they have no need for a kitchen renovation. Now, additionally, advertising can have a negative effect on the natural beauty of the environment. People are often less able to enjoy the beauty of the natural surroundings if there are large advertisements blocking their view of the landscape or distracting them from the natural beauty around them. Let's face it. No matter how beautiful an area of nature is to begin with, its beauty is damaged by visible advertisements. So...like, for example, this happens with big advertisements on the side of roads, huge billboards. Say there's a road passing through a beautiful area in the mountains, but there are all these big billboards advertising restaurants and products along the side of the road. The land is naturally very beautiful, but you can't fully appreciate it. The big billboard advertisements get in the way. 托福TPO48口语Task6题目： Using the points and examples from the lecture, explain two ways that advertising can negatively affect the environment. 托福TPO48口语Task6满分范文： The lecture talks about two negative impacts of advertising on the environment. The first drawback refers to the waste of natural resources. For example, I receiveda whole bunch of booklets promoting various ways of kitchen renovation service. But this was irrelevant to me and a total waste of trees because the apartment I lived was rented and many people would throw the advertising mails into dustbin just as I did. The second shortcoming concerns the natural beauty of the environment. Huge billboards advertising restaurants and products along the side of the road will block the view of the landscape or distract people from the natural beauty. 以上是给大家整理的托福TPO48口语Task6听力文本+题目+满分范文，希望对你有所帮助!。

目录tpo48Passage2:Determining Dinosaur Diet (1)译文：探究恐龙饮食 (2)练习题目 (3)答案 (9)文章小结题解析 (9)背景知识 (9)tpo48Passage2:Determining Dinosaur Diet①Determining what extinct dinosaurs ate is difficult,but we can infer some aspects of their dietary preferences.Traditionally,this information has been derived from direct evidence,such as stomach contents,and indirect evidence,such as establishing a correlation between particular body characteristics and diets of living animals and then inferring habits for dinosaurs.②Animals such as house cats and dogs have large,stabbing canine teeth at the front of the mouth and smaller,equally sharp teeth farther back in their jaws.Many of these animals are also armed with sharp claws.The advantage of teeth and claws as predatory tools is obvious.Now consider animals like cows,horses,rabbits,and mice. These animals have flat teeth at the back of the jaw that are analogous to and have the same function as grindstones.Unlike the meat-slicing and stabbing teeth of carnivores,the teeth of these animals grind and shred plant material before digestion.③More clues exist in other parts of the skull.The jaw joint of carnivores such as dogs and cats has the mechanical advantage of being at the same level as the tooth row, allowing the jaws to close with tremendous speed and forcing the upper teeth to occlude against the lower teeth with great precision.In herbivorous animals,rapid jaw closure is less important.Because the flat teeth of herbivores work like grindstones,however,the jaws mush move both side to side and front to back.The jaw joints of many advanced herbivores,such as cows,lie at a different level than the tooth row,allowing transverse tearing,shredding,and compression of plant material. If we extend such observations to extinct dinosaurs,we can infer dietary preferences (such as carnivory and herbivory),even though we cannot determine the exact diet. The duck-billed dinosaurs known as hadrosaurs are a good example of a group whose jaw joint is below the level of the tooth row,which probably helped them grind up tough,fibrous vegetation.④Paleontologists would like to be much more specific about a dinosaur’s diet than simply differentiating carnivore from herbivore.This finer level of resolution requires direct fossil evidence of dinosaur meals.Stomach contents are only rarely preserved, but when present,allow us to determine exactly what these animals were eating.⑤In the stomach contents of specimens of Coelophysis(a small,long-necked dinosaur)are bones from juvenile animals of the same species.At one time,thesewere thought to represent embryonic animals,suggesting that this small dinosaur gave birth to live young rather than laying eggs.Further research indicated that the small dinosaurs were too large and too well developed to be prehatchling young.In addition,the juveniles inside the body cavity were of different sizes.All the evidence points to the conclusion that these are the remains of prey items and that,as an adult,Coelophysis was at least in part a cannibal.⑥Fossilized stomach contents are not restricted to carnivorous dinosaurs.In a few rare cases,most of them“mummies”(unusually well preserved specimens), fossilized plant remains have been found inside the body cavity of hadrosaurs.Some paleontologists have argued that these represent stream accumulations rather than final meals.The best known of these cases is the second Edmontosaurus mummy collected by the Sternbergs.In the chest cavity of this specimen,which is housed in the Senckenberg Museum in Germany,are the fossil remains of conifer needles, twigs,seeds,and fruits.Similar finds in Corythosaurus specimens from Alberta, Canada,have also been reported,indicating that at least two kinds of Late Cretaceous hadrosaurs fed on the sorts of tress that are common in today’s boreal woodlands.⑦A second form of direct evidence comes from coprolites(fossilized bodily waste). Several dinosaur fossil localities preserve coprolites.Coprolites yield unequivocal evidence about the dietary habits of dinosaurs.Many parts of plants and animals are extremely resistant to the digestive systems of animals and pass completely through the body with little or no alteration.Study of coprolites has indicated that the diets of some herbivorous dinosaurs were relatively diverse,while other dinosaurs appear to have been specialists,feeding on particular types of plants.The problem with inferring diets from coprolites is the difficulty in accurately associating a particular coprolite with a specific dinosaur.译文：探究恐龙饮食①确定灭绝的恐龙吃什么是困难的，但我们可以推断出他们的饮食偏好的某些方面。

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Chinese Population Growth Increases 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. It is estimated that the Chinese population by 1600 was close to 150 million.The transition between the Ming and Qing dynasties(the seventeenth century)may have seen a decline,but from 1741 to 1851 the annual figures rose steadily and spectacularly,perhaps beginning with 143 million and ending with 432 million.If we accept these totals,we are confronted with a situation in which the Chinese population doubled in the 50 years from 1790 to 1840.If,with greater caution,we assume lower totals in the early eighteenth century and only 400 million in 1850,we still face a startling fact:something like a doubling of the vast Chinese population in the century before Western contact,foreign trade,and industrialization could have had much effect. To 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. Confronted 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 since 1368.Assuming that China’s population in 1400 was about 80 million,the economist Dwight Perkins concludes that its growth to 700 million or more in the 1960s was made possible by a steady increase in the grain supply,which evidently grew five or six times between 1400 and 1800 and rose another 50 percent between 1800 and 1965.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 per unit of land. This 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. Productivity in agriculture was also improved by capital investments,first of all in irrigation.From 1400 to 1900 the 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. Paragraph 1 Increases 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. 1.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. merce,industrialization,and development are common features of the Western experience. B.Trade,industrialization,and development accelerated social change in Western societies. C.Trade and industrialization brought about development in Western societies. D.In Western societies,social change provided the conditions for development in。