【威学教育】王鑫托福阅读TPO27-3阅读文本
托福TPO27口语Task3阅读文本+听力文本+题目+满分范文
(man) How come?
(woman) Well, the cost, for one thing, they are just not being realistic.
(man)ห้องสมุดไป่ตู้Even compare to the price of textbooks?
为了帮助大家高效备考托福，为大家带来托福 TPO27 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 TPO27 口语 Task3 阅读文本：
Switch to Electronic Textbooks
The university will begin switching from traditional-bound textbooks to electronic textbooks early next year. University students will be able to download the content of their required textbooks to a reading device and read the material directly from the device’s screen. While the cost of the device is around $200, it is a one-time expense. Considering the rising cost of textbooks, students will save money in the long run since purchasing electronic books for their classes is much less expensive than buying regular textbooks. Furthermore, the university believes the device will be an effective study aid because it is simple to operate and offers features such as highlighting of text and note-taking.
2019年TPO27托福口语Task3原文及参考答案
2019年TPO27托福口语Task3原文及参考答案TPO27口语Task3题目：Switch to Electronic TextbooksThe university will begin switching from traditional-bound textbooks to electronic textbooks early next year. University students will be able to download the content of their required textbooks to a reading device and read the material directly from the device’sscreen. While the cost of the device is around $200, it is a one-timeexpense.Considering the rising cost of textbooks, students will save money in the long run since purchasing electronic books for their classes is much less expensive than buying regular textbooks.Furthermore, the university believes the device will be an effective study aid because it is simple to operate and offers features such as highlighting of textand note-taking.ConversationNow listen to two students discussing the article.Woman： Oh, no, did you see this?Man：Yeah, why? You don’t like the idea?Woman： Not at all!Man： How come?Woman： Well, the cost, for one thing, they are just not being realistic.Man： Even compare to the price of textbooks?Woman： We ll, sure, textbooks aren’t cheap, but do you think people are only gonna use one device the whole time they are at university? What happens if yours breaks? You have to buy a new one. Or they come out with some fancy new features. Wouldn't you want to get a new one then?Man： Yeah, I see what you mean. A lot of people would probably want to replace theirs with the latest version.Woman： Right! Maybe even every year and that can add up.Man：True, but, don’t you agree it’ll make studying and preparing for classes a lot easier?Woman：I don’t think everybody is gonna think it’s so great.Man： What do you mean?Woman：Well., it’s only helpful if it’s easy to use and, well, this thing is pretty small. It’s only about 18 or 20 centimeters tall.Man：Oh, really? So that means the screen’s pretty small.Woman： Right, and I heard that the key pad or control buttons, they are small, too. So if you have normal-sized fingers, it’s not so easy to select an item or get it to function right, you know, to do stuff like highlighting or underlining.Man：I hadn’t thought of that.Woman： So what good are all those fancy features ifit’s hard to use them? Besides, I like the old-fashioned wayof studying material： writing notes on the page and underlining or highlighting important sections of the book. I’m more comfortable with that.QuestionThe woman expresses her opinion about the university’s plan. Briefly summarize theplan then state her opinion and explain the reasons she gives for holding that opinion.Key Points1. less expensive in the long run2. more effective featuresTPO27口语Task3参考答案(范文模板)：The woman doesn’t agree with the school’s plan to switch from traditional text-books to electronic books. According to the school, even though the device is expensive, they believe that it will save students money in the long run cos the cost of electronic books is so much lower than regular text-books, but the woman says that if someone’s device breaks, they would have to buy a new one and that can get expensive. Plus, they may come out with a new model every year that people will want as well. The school also notesthat the device will be an effective study-aid cos it can help students take notes and highlight information, but the woman points out that the device isn’t really big and the buttons are small so even if it has a lot of features, itwill stil l be difficult to use and she’s more comfortable writing in a book than using a device.。
TPO27 R-3 原文翻译
TPO27 R-3 原文翻译Predator-Prey Cycles捕食者是怎样影响被捕食者的数量的呢？答案并不是想象中那么简单的。
麋鹿通过穿越冬天的冰层和到达了在苏必略路的罗亚尔岛，在那他们因为和捕食者分隔开来就更自由了。
当狼在晚一点的时候到达那座岛的时候，自然学家都认为，狼对控制麋鹿的数量起到了关键的作用。
但是，严密的研究已经说明，并不是这样的。
狼吃掉的大部分是年老的，或是已经生病的动物，他们本身就不会存活很久了。
总的来说，麋鹿的数量是由食物的可利用性，疾病，和其他的一些条件，而不是因为狼。
当实验性的数量被设置在简单的实验条件下，捕食者经常吃掉了所有的被捕食者，然后因为没有东西吃，自己灭绝了。
但是，如果能给被捕食动物提供如同在野外的安全的区域，被捕食动物的数量会降低到很低的数值，但不会灭绝。
低的被捕食动物数量造成了捕食者的食物不足，使捕食者的数量下降。
当这个情况发生的时候，被捕食动物的数量又会反弹。
这样，在一定的时候，捕食者和被捕食者的数量会持续地在这种循环中变化。
这种数量的循环是小型哺乳动物的特性，有时候这种循环的出现是由捕食者带来的。
生态学家对野兔数量的研究已经显示，北美“雪鞋野兔”一直遵守着大约以十年为一周期的循环。
在一个典型的循环中，其数量会以十倍到三十倍的减少，甚至会出现百倍的改变会出现。
有两种因素会导致这种循环：食物和捕食者。
“雪鞋野兔”比较喜欢的食物是柳木和桦树树枝。
当野兔的密度增加的时候，这些树枝的数量就会减少，迫使野兔去吃一些低质量的，高纤维食物。
随之而来的是低生育率，低成活率，低生长率，所以产生了对应的野兔数量的减少反应。
一旦野兔数量减少了，树枝的数量会需要两到三年去恢复。
雪鞋野兔的主要捕食者是加拿大山猫。
加拿大山猫呈现了平行于野兔的十年鼎盛循环。
当野兔的数量下降的时候，当山猫的食物供给减少，山猫数量也会发生同样的变化。
是什么造成了捕食者和被捕食者的振幅呢？是野兔数量的增长使得植物被过度破坏，随之导致了野兔的减少？还是山猫的增加导致了野兔被过度捕捉？在1992年，Charles Krebs 和其合作者的野外试验提供了答案。
【威学教育王鑫】托福阅读TPO2-1文本
【王鑫托福阅读】TPO2-1阅读文本TPO2TPO2-1 Desert Formation1. The word threatened in the passage is closest in meaning toA. RestrictedB. EndangeredC. PreventedD. Rejected2. According to paragraph 3, the loss of natural vegetation has which of the following consequences for soil?A. Increased stony contentB. Reduced water absorptionC. Increased numbers of spaces in the soilD. Reduced water runoffThe deserts, which already occupy approximately a fourth of the Earth's land surface, have in recent decades been increasing at an alarming pace. The expansion of desert like conditions into areas where they did not previously exist is called desertification. It has been estimated that an additional one-fourth of the Earth's land surface is threatened by this process.Desertification is accomplished primarily through the loss of stabilizing natural vegetation and the subsequent accelerated erosion of the soil by windand water. In some cases the loose soil is blown completely away, leaving a stony surface. In other cases, the finer particles may be removed, while the sand-sized particles are accumulated to form mobile hills or ridges of sand.Even in the areas that retain a soil cover, the reduction of vegetation typically results in the loss of the soil's ability to absorb substantial quantities of water. The impact of raindrops on the loose soil tends to transfer fine clay particles into the tiniest soil spaces, sealing them and producing a surface that allows very little water penetration. Water absorption is greatly reduced; consequently runoff is increased, resulting in accelerated erosion rates. The gradual drying of the soil caused by its diminished ability to absorb water results in the further loss of vegetation, so that a cycle of progressive surface deterioration is established.In some regions, the increase in desert areas is occurring largely as the result of a trend toward drier climatic conditions. Continued gradual global warming has produced an increase in aridity for some areas over the past few thousand years. The process may be accelerated in subsequent decades if global warming resulting from air pollution seriously increases.3. The word delicate in the passage is closest in meaning toA. FragileB. PredictableC. ComplexD. Valuable4. According to paragraph 5, in dry periods, border areas have difficultyA. Adjusting to stresses created by settlementB. Retaining their fertility after desertificationC. Providing water for irrigating cropsD. Attracting populations in search of food and fuel5. The word progressively in the passage is closest in meaning toA. OpenlyB. ImpressivelyC. ObjectivelyD. Increasingly6. According to paragraph 6, which of the following is often associated with raising crops?A. Lack of proper irrigation techniquesB. Failure to plant crops suited to the particular areaC. Remova丨 of the original vegetationD. Excessive use of dried animal waste;mlluwmg isThere is little doubt, however, that desertification in most areas results primarily from human activities rather than natural processes. The semiarid lands bordering the deserts exist in a delicate ecological balance and are limited in their potential to adjust to increased environmental pressures. Expanding populations are subjecting the land to increasing pressures to provide them with food and fuel. In wet periods, the land may be able to respond to these stresses. During the dry periods that are common phenomena along the desert margins, though, the pressure on the land is often far in excess of its diminished capacity, and desertification results.Four specific activities have been identified as major contributors to the desertification processes: overcultivation, overgrazing, firewood gathering, and overirrigation. The cultivation of crops has expanded into progressively drier regions as population densities have grown. These regions are especially likely to have periods of severe dryness, so that crop failures are common. Since the raising of most crops necessitates the prior removalof the natural vegetation, crop failures leave extensive tracts of land devoid of a plant cover and susceptible to wind and water erosion.7.The phrase devoid of in the passage is closest in meaning to A Consisting of B Hidden by C Except for D Lacking inThe raising of livestock is a major economic activity in semiarid lands, where grasses are generally the dominant type of natural vegetation.The consequences of an excessive number of livestock grazing in an area are the reduction of the vegetation cover and the trampling and pulverization of the soil. This is usually followed by the drying of the soil and accelerated erosion.Firewood is the chief fuel used for cooking and heating in many countries. The increased pressures of expanding populations have led to the removal of woody plants so that many cities and towns are surrounded by large areas completely lacking in trees and shrubs. The increasing use of dried animal waste as a substitute fuel has also hurt the soil because this valuable soil conditioner and source of plant nutrients is no longer being returned to the land.D.Bring salts to the surfaceThe final major human cause of desertification is soil salinization resulting from overirrigation. Excess water from irrigation sinks down into the water table. If no drainage system exists, the water table rises, bringing dissolved salts to the surface. The water evaporates and the salts are left behind, creating a white crustal layer that prevents air and water from reaching the underlying soil.9. All of the following are mentioned in the passage as contributing to desertification EXCEPTA. Soil erosionB. Global warmingC. Insufficient irrigationD. The raising of livestock10. 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. Desertification is a significant problem because it is so hard to reverse and affects large areas of land and great numbers of people.B. Slowing down the process of desertification is difficult because of population growth that has spread over large areas of land.C. The spread of deserts is considered a very serious problem that can be solved only if large numbers of people in various countries are involved in the effort.D. Desertification is extremely hard to reverse unless the population is reduced in the vast areas affected.The extreme seriousness of desertification results from the vast areas of land and the tremendous numbers of people affected, as well as from the great difficulty of reversing or even slowing the process.Once the soil has been removed by erosion, only the passage of centuries or millennia will enable new soil to form. In areas where considerable soil still remains, though, a rigorously enforced program of land protection and cover-crop planting may make it possible to reverse the present deterioration of the surface.11. It can be inferred from the passage that the author most likely believes which of the following about the future of desertification?A. Governments will act quickly to control further desertification.B. The factors influencing desertification occur in cycles and will change in the future.C. Desertification will continue to increase.D. Desertification will soon occur in all areas of the world■The raising of livestock is a major economic activity in semiarid lands, where grasses are generally the dominant type of natural vegetation.^The consequences of an excessive number of livestock grazing in an area are the reduction of the vegetation cover and the trampling and pulverization of the soil. ■This is usually followed by the drying of the soil and accelerated erosion._12. Look at the four squares [■] that indicate where the following sentence can be added to the passage. Where would the sentence best fit?This economic reliance on livestock in certain regions makes large tracts of land susceptible to overgrazing.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 answer choices do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points. Many factors have contributed to the great increase in desertification in recent decades.A. Growing human populations and the agricultural demands that come with such growth have upset the ecological balance in some areas and led to the spread of deserts.B. As periods of severe dryness have become more common, failures of a number of different crops have increased.C. Excessive numbers of cattle and the need for firewood for fuel have reduced grasses and trees, leaving the land unprotected and vulnerable.D. Extensive irrigation with poor drainage brings salt to the surface of the soil, a process that reduces water and air absorption.E. Animal dung enriches the soil by providing nutrients for plant growth.F. Grasses are generally the dominant type of natural vegetation in semiarid lands.。
新托福TPO27阅读原文及译文(三)
新托福TPO27阅读原文(一)：Crafts in the Ancient Near EastTPO27-1：Crafts in the Ancient Near EastSome of the earliest human civilizations arose in southern Mesopotamia, in what is now southern Iraq, in the fourth millennium B.C.E. In the second half of the millennium, in the south around the city of Uruk, there was an enormous escalation in the area occupied by permanent settlements. A large part of that increase took place in Uruk itself, which became a real urban center surrounded by a set of secondary settlements. While population estimates are notoriously unreliable, scholars assume that Uruk inhabitants were able to support themselves from the agricultural production of the field surrounding the city, which could be reached with a daily commute. But Uruk’s dominant size in the entire region, far surpassing that of other settlements, indicates that it was a regional center and a true city. Indeed, it was the first city in human history.The vast majority of its population remained active in agriculture, even those people living within the city itself. But a small segment of the urban society started to specialize in nonagricultural tasks as a result of the city’s role as a regional center. Within the productive sector, there was a growth of a variety of specialist craftspeople. Early in the Uruk period, the use of undecorated utilitarian pottery was probably the result of specialized mass production. In an early fourth-millennium level of the Eanna archaeological site at Uruk, a pottery style appears that is most characteristic of this process, the so-called beveled-rim bowl. It is a rather shallow bowl that was crudely made in a mold; hence, in only a limited number of standard sizes. For some unknown reason, many were discarded, often still intact, and thousands have been found all over the Near East. The beveled-rim bowl is one of the most telling diagnostic finds for identifying an Uruk-period site. Of importance is the fact that it was produced rapidly in large amounts, most likely by specialists in a central location.A variety of documentation indicates that certain goods, once made by a family member as one of many duties, were later made by skilled artisans. Certain images depict groups of people, most likely women, involved in weaving textiles, an activitywe know from later third-millennium texts to have been vital in the economy and to have been centrally administered. Also, a specialized metal-producing workshop may have been excavated in a small area at Uruk. It contained a number of channels lined by a sequence of holes, about 50 centimeters deep, all showing burn marks and filled with ashes. This has been interpreted as the remains of a workshop where molten metal was scooped up from the channel and poured into molds in the holes. Some type of mass production by specialists were involved here.Objects themselves suggest that they were the work of skilled professionals. In the late Uruk period(3500-3100 B.C.E.), there first appeared a type of object that remained characteristic for Mesopotamia throughout its entire history: the cylinder seal. This was a small cylinder, usually no more than 3 centimeters high and 2 centimeters in diameter, of shell, bone, faience (a glassy type of stoneware), or various types of stones, on which a scene was carved into the surface. When rolled over a soft material----primarily the clay of bullae (round seals), tablets, or clay lumps attached to boxes, jars, or door bolts----the scene would appear in relief, easily legible. The technological knowledge needed to carved it was far superior to that for stamp seals, which had happened in the early Neolithic period (approximately 10,000-5000 B.C.E.). From the first appearance of cylinder seals, the carved scenes could be highly elaborate and refined, indicating the work of specialist stone-cutters. Similarly, the late Uruk period shows the first monumental art, relief, and statuary in the round, made with a degree of mastery that only a professional could have produced.TPO27-1译文：古代近东的工匠一些最早的人类文明是在公元前四千年前的南美索不达米亚出现的，现在这片区域处于南伊拉克。
威学教育王鑫托福阅读TPO33阅读文本
【王鑫托福阅读】托福TPO3-3阅读文本TPO3TPO3-3 The Long Term Stability of Ecosystems1. The word “particular” in the passage is closest in meaning toA. naturalB. finalC. specificD. complex2. According to paragraph 1, which of the following is NOT true of climax communitiesA. They occur at the end of a succession.B. They last longer than any other type of community.C. The numbers of plants in them and the mix of species do not change.D. They remain stable for at least 500 years at a time.3. According to paragraph 2, which of the following principles of ecosystems can be learned by studying a pondA. Ecosystem properties change more slowly than individuals in the system.B. The stability of an ecosystem tends to change as individuals are replaced.C. Individual organisms are stable from one year to the next.D. A change in the members of an organism does not affect an ecosystem’ s propertiesPlant 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.4. According to paragraph 3, ecologists once believed that which of the following illustrated the most stable ecosystemsA. Pioneer communitiesB. Climax communitiesC. Single-crop farmlandsD. Successional plant communities5. According to paragraph 4, why is the question of ecosystem stability complicated reasons for ecosystem change are not always clear.B. Ecologists often confuse the word “stability” with the word“ resilience. ”C. The exact meaning of the word “ stability ” is debated by ecologists.D. There are many different answers to ecological questions.6. According to paragraph 4, which of the following is true of climax communitiesA. They are more resilient than pioneer communities.B. They can be considered both the most and the least stable communities.C. They are stable because they recover quickly after major disturbances.D. They are the most resilient communities because they change the least over time.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 entirecrop. 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.7. Which of the following can be inferred from paragraph 5 about redwood forestsA. They become less stable as they mature.B. They support many species when they reach climax.C. They are found in temperate zones.D. They have reduced diversity during mid-successional stages.8. The word “guarantee” in the passage is closest in meaning toA. increaseB. ensureC. favorD. complicateparagraph 5, why does the author provide the information that “A fifteen-speed racing bicycle is more likely to break down than a child’ s tricycle”A. To illustrate a general principle about the stability of systems by using an everyday exampleB. To demonstrate that an understanding of stability in ecosystems can be applied to help understand stability in other situationsC. To make a comparison that supports the claim that, in general, stability increases with diversityD. To provide an example that contradicts mathematical models of ecosystemsEven 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 redwood forest 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.10. The word “pales” in the passage is closest in me aning toA. increases proportionallyB. differsC. loses significanceD. is common11. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage Incurred choices change the meaning in important ways or leave out essential information.A. Ecologists now think that the stability of an environment is a result of diversity rather than patchiness.B. Patchy environments that vary from place to place do not often have high species diversity.C. Uniform environments cannot be climax communities because they do not support as many types of organisms as patchy environments.D. A patchy environment is thought to increase stability because it is able to support a wide variety of organisms.12. The word “adjacent” in the passage is closest in meaning toEcologists are especially interested to know what factors contribute to the resilience of communities because climax communities all over the world arebeing 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.B. stableC. fluidD. neighboring■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 its13. Look at the four squares [■] that indicate where the following senten ce could be added to the passage. Where would the sentence best fitIn fact, damage to the environment by humans is often much more severe than damage by natural events and processes.14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points. The process of succession and the stability of a climax community can change over time.A. The changes that occur in an ecosystem from the pioneer to the climax community can be seen in one human generation.B. A high degree of species diversity does not always result in a stable ecosystem.C. Disagreements over the meaning of the term "stability" make it difficult to identify the most stable ecosystems.D. Ecologists agree that climax communities are the most stable types of ecosystems.E. The level of resilience in a plant community contributes to its long-term stability.F. The resilience of climax communities makes them resistant to destruction caused by humans.。
【威学教育王鑫】想掌握托福阅读考点,就要多做托福真题
威学教育|专注雅思、托福等出国考试培训网址：想掌握托福阅读考点，就要多做托福真题在托福考试中流传着这样一句话：得词汇者得阅读，得阅读者得托福！在威学教育经常会遇到很多学生来上托福课，难的单词到是认识很多，但是题眼的单词是抓不到的，托福阅读出题题眼的单词并不都是高深的词汇，因为在表达中不管是中英文都是用简单明了的语言来表达思想的，而很多同学着眼于8000词汇中通常不用的词汇，而抛弃了高中词汇的3500词或大学的4500词，那么这样是不是在解题的时候容易抓不到意思呢?切忌，新托福阅读词汇是关键，但重中之重是重点词汇。
威学教育托福导师sally指出，不少学生对于该如何做题一直纠结不清，到底是先看文章再做题，还是直接跳过文章去做题目?每一种方法都有每一种方法的利与弊，比如说学生们也自己总结出一套方法，先看一段，然后做相应的题目，这样既可以读到文章心理踏实也可以及时记住文章中的内容，此种方法也不失为一种好方法。
前面的三种方法都可以用来做题，也都有各自的好处。
那么以上三种方法，大家可以课下在做练习的时候都试用一下，哪一种方法最适合自己就用哪一种方法。
巧用托福阅读真题让考点清晰(1)构成因果处是考点，两事物或者多事物间的因果顺序关系要弄清楚。
(2)两事物或对象对比、类比、比较处是考点。
当出现此类语言叙述时，必须要弄清楚两事物或几个事物间的相同点，相异点的特征分别是什么，他们之间有什么联系或者关联。
时间，空间，程度或者间接转折均能构成对比或者比较其相似或相异性。
(3)事物叙述的缺陷处所在是考点。
此时要弄清缺陷与所叙述的事物不足处是什么，如果文章提出了改进方法，还必须知道改进和或弥补的方法又是什么，在众多方法中，作者到底同意或者赞同哪一个，一般来说是最后一个观点。
)(4)特殊语言处是考点，例如：最高级和比较级处，各种长难复合句，高级词汇所在句子以及特殊易混的短语习语处。
(5)强转折是考点，引入新观点或者反驳前所叙述的主题处是考点，其中转折的方式很多，除了传统的however, but, yet外，其他方式的转折也必须注意，尤其是一个概念向另一个概念过渡的地方。
托福备考托福阅读34套TPO样题+解析+译文26—3 Sumer and the First Cities of the Ancient Near East
托福考试 复习TPO 26—3 Sumer and the First Cities of the Ancient Near East原文：【1】The earliest of the city states of the ancient Near East appeared at the southern end of the Mesopotamian plain, the area between the Tigris and Euphrates rivers in what is now Iraq. It was here that the civilization known as Sumer emerged in its earliest form in the fifth millennium. At first sight, the plain did not appear to be a likely home for a civilization. There were few natural resources, no timber, stone, or metals. Rainfall was limited, and what water there was rushed across the plain in the annual flood of melted snow. As the plain fell only 20 meters in 500 kilometers, the beds of the rivers shifted constantly. It was this that made the organization of irrigation, particularly the building of canals to channel and preserve the water, essential. Once this was done and the silt carried down by the rivers was planted, the rewards were rich: four to five times what rain-fed earth would produce. It was these conditions that allowed an elite to emerge, probably as an organizing class, and to sustain itself through the control of surplus crops.【2】It is difficult to isolate the factors that led to the next development—the emergence of urban settlements. The earliest, that of Eridu, about 4500 B.C.E., and Uruk, a thousand years later, center on impressive temple complexes built of mud brick. In some way, the elite had associated themselves with the power of the gods. Uruk, for instance, had two patron gods—Anu, the god of the sky and sovereign of all other gods, and Inanna, a goddess of love and war—and there were others, patrons of different cities. Human beings were at their mercy. The biblical story ofthe Flood may originate in Sumer. In the earliest version, the gods destroy the human race because its clamor had been so disturbing to them.【3】It used to be believed that before 3000 B.C.E. the political and economic life of the cities was centered on their temples, but it now seems probable that the cities had secular rulers from earliest times. Within the city lived administrators, craftspeople, and merchants. (Trading was important, as so many raw materials, the semiprecious stones for the decoration of the temples, timbers for roofs, and all metals, had to be imported.) An increasingly sophisticated system of administration led in about 3300 B.C.E. to the appearance of writing. The earliest script was based on logograms, with a symbol being used to express a whole word. The logograms were incised on damp clay tablets with a stylus with a wedge shape at its end. (The Romans called the shape cuneus and this gives the script its name of cuneiform.) Two thousand logograms have been recorded from these early centuries of writing.A more economical approach was to use a sign to express not a whole word but a single syllable. (To take an example: the Sumerian word for " head” was “sag.” Whenever a word including a syllable in which the sound “sag” was to be written, the sign for “sag" could be used t o express that syllable with the remaining syllables of the word expressed by other signs.) By 2300 B.C.E. the number of signs required had been reduced to 600, and the range of words that could be expressed had widened. Texts dealing with economic matters predominated, as they always had done; but at this point works of theology, literature, history, and law also appeared.【4】Other innovations of the late fourth millennium include the wheel, probably developed first as a more efficient way of making pottery and then transferred to transport. A tablet engraved about 3000 B.C.E. provides the earliest known example from Sumer, a roofed boxlike sledge mounted on four solid wheels. A major development was the discovery, again about 3000 B.C.E., that if copper, which had been known in Mesopotamia since about 3500 B.C.E., was mixed with tin, a much harder metal, bronze, would result. Although copper and stone tools continued to be used, bronze was far more successful in creating sharp edges that could be used as anything from saws and scythes to weapons. The period from 3000 to 1000 B.C.E., when the use of bronze became widespread, is normally referred to as the Bronze Age.题目：1.Which of the following is NOT mentioned in paragraph 1 as a disadvantage of the Mesopotamian plain?A.There was not very much rainfall for most of the year.B.Melting snow caused flooding every year.C.The silt deposited by rivers damaged crops.D.Timber, stone and metals were not readily available.2.According to paragraph 1, which of the following made it possible for anelite to emerge?A.New crops were developed that were better suited to conditions on theMesopotamian plain.B.The richest individuals managed to gain control of the most valuable cropland.C.Control over the few available natural resources made some people four to five times richer than everyone else.D.The building of canals to increase agricultural output required organization.3.The word “sustain”in the passage（paragraph 1）is closest in meaning toA.defend.B.promote.C.maintain.D.transform.4.According to paragraph 2, Eridu and Uruk are examples of urbansettlements thatcked the features usually found in other early urban settlements.B.developed around religious buildings.C.grew much more rapidly than most of the urban settlements found in Sumer.D.were mysteriously destroyed and abandoned.5.The word “sovereign"in the passage is closest in meaning toA.counselor.B.master.C.defender.D.creator.6.According to paragraph 3, which of the following led to the appearanceof writing?A.An increasingly sophisticated administrative system.B.Coordination between secular and religious leaders.C.The large volume of trade, particularly imports.D.A rapidly expanding and changing population.7.In paragraph 3, why does the author provide the information that the number of signs in use had dropped from 2,000 to 600 by 2300 B.C.E.?A.T o argue that the development of writing involved periods of growth followed by periods of decline.B.To demonstrate that earlier written texts used a larger vocabulary than later texts, which were aimed at a broader audience.C.To support the claim that the range of words expressed by logograms varied widely depending on time period and type of text.D.T o provide evidence for the increased efficiency of using signs to express syllables rather than whole words.8.According to paragraph 3, ancient texts most commonly dealt withA.theology.B.literature.C.economics.w.9.According to paragraph 4, the earliest wheels probablyA.were first developed in areas outside Mesopotamia.B.were used to make pottery.C.appeared on boxlike sledges.D.were used to transport goods between cities.10.The word “engraved”in the passage(paragraph 4)is closest in meaning toA.carved.B.produced.C.dated.D.discovered.11.Which of the sentences below best expresses the essential information inthe highlighted sentence in the passage paragraph 4 ? Incorrect choices change the meaning in important ways or leave out essential information.A.Also around 3000B.C.E., it was discovered that mixing copper, known from about 3500 B.C.E., with tin would create a much harder metal known as bronze.B.Although copper had been known since 3500 B.C.E in Mesopotamia, the discovery of bronze did not occur until around 3000 B.C.E.C.Another major development around 3000 B.C.E. was the discovery that copper could be mixed with a much harder metal known as tin.D.The development of bronze by mixing copper and tin probably occurred around 3000 B.C.E. but may have happened as early as 3500 B.C.E.12.The word “widespread”in the passage(paragraph 4)is closest in meaning toA.obvious.B.significant.C.necessary.mon.13. Look at the four squares [■]that indicate where the following sentence could be added to the passage.Where would the sentence best fit? City life was diverse, and the population was engaged in a variety of occupations.It used to be believed that before 3000 B.C.E. the political and economic life of the cities was centered on their temples, but it now seems probable that the cities had secular rulers from earliest times. ■【A】Within the city lived administrators, craftspeople, and merchants. (Trading was important, as so many raw materials,the semiprecious stones for the decoration of the temples, timbers for roofs,and all metals, had to be imported.) ■【B】An increasingly sophisticated system of administrationled in about 3300 B.C.E. to the appearance of writing. ■【C】The earliest script was based on logograms, with asymbol being used to express a whole word. ■【D】The logograms were incised on damp clay tablets with a stylus with a wedge shape at its end. (The Romans called the shape cuneus and this gives the script its name of cuneiform.) Two thousand logograms have been recorded from these early centuries of writing. A more economical approach wasto use a sign to express not a whole word but a single syllable. (To take an example: the Sumerian word for " head” was “sag.” Whenever a wordincluding a syllable in which the sound “sag” was to be written, the sign for“sag" could be used to express that syllable with the remaining syllablesof the word expressed by other signs.) By 2300 B.C.E. the number of signs required had been reduced to 600, and the range of words that could be expressed had widened. Texts dealing with economic matters predominated, as they alwayshad done; but at this point works of theology,literature, history, and lawalso appeared.14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minorideas in the passage. This question is worth 2 points.Irrigation made it possible for the civilization known as Sumer to arise on the Mesopotamian plain in the fifth millennium B.C.E.A.The scarcity of natural resources on the plain made it necessary for a powerful elite to emerge and take charge of trade and imports.B.The economy of each city was based on a craft such as pottery or metal working, and the city of Eridu was known for its saws, scythes and weapons.C.Writing appeared in the form of logograms and later developed into a system using signs to represent syllables rather than whole words.D.Priests were powerful figures in the ancient civilization and controlled the political and economic life of the cities.E.The earliest city states had one or more patron gods and were built around central temple complexes.F.The development of the wheel and the creation of bronze were important innovations in Sumer答案：1.A选项的rainfall和B的melting snow做关键词定位至第五句，都正确，不选；C的silt 确实讲过，但并没讲damaged crops，所以C错，选；D的timber, stone and metals定位至第四句，正确，不选。
TPO-27 Reading 3解析
Q1正确答案：B解析：定位到第3-4句，“naturalists widely assumed...Careful studies have demonstrated…”, 第3句说人们认为狼对鹿的数量控制起到了重要作用，第4句话说研究否定了人们的判断，B选项与原文的意思和逻辑关系对应。
文中没有wolves follow moose的意思，排除A; C与段落最后一句话矛盾; D在文中没有依据。
Q2正确答案：B解析：rebound，弹回，反弹，回升；近义词是recover, 恢复。
根据上下文的逻辑关系可以推断出词义，词汇所在句的意思是“当捕食者的数量下降，被捕食者的数量会rebound”，recover最符合句子前后的逻辑关系；也可以通过词根词缀分析rebound。
bound本来就是跳跃的意思，加re-前缀就是再次跳跃，也就是反弹。
Q3正确答案：A解析：考察理解段落意思。
题干中的实验环境下捕猎者灭绝的情况出现在第1句，但后面立刻出现了however，出现了转折。
下文叙述的内容是在提供安全环境的条件下，捕食者和被捕食者的数量可以保持一个cyclical pattern，被捕食者就不会灭绝。
所以实验环境下捕猎者灭绝的情况是并不能准确地反映真实的野外情况，A正确。
Q4正确答案：D解析：根据第三段最后一句话，排除A; 根据对第2段大意的理解，确定正常情况下捕食者是不会灭绝消失的，排除B；第三段第2句出现了ten-year cycle，但是仅是对野兔的描写，并不适用于全部哺乳动物，排除C。
根据第二段第2句，被捕食者在现实生活中可以居于安全的远离捕食者的地方，确定D正确。
Q5正确答案：C解析：roughly，大约，大致，差不多；近义词是approximately，大约。
rough 作为形容词有“不确切的，粗略的”意思，可据此推断roughly作为副词的意思。
Q6正确答案：A解析：generate，产生，引起；近义词是produce。
托福TPO27阅读Passage3原文文本+题目+答案解析
托福TPO27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TPO27阅读Passage3原文文本+题目+答案解析，希望对大家备考有所帮助。
Predator-Prey CyclesHow do predators affect populations of the prey animals?The answer is not as simple as might be thought.Moose reached Isle Royale in Lake Superior by crossing over winter ice and multiplied freely there in isolation without predators.When wolves later reached the island,naturalists widely assumed that the wolves would play a key role in controlling the moose population.Careful studies have demonstrated,however,that this is not the case.The wolves eat mostly old or diseased animals that would not survive long anyway.In general,the moose population is controlled by food availability,disease and other factors rather than by wolves.捕食者是怎样影响被捕食者的数量呢?答案并不是想象中那么简单。
麋鹿通过穿越冬天的冰层到达了在苏必略湖的罗亚尔岛，并由于没有捕食者而自由繁殖。
TPO 27阅读第三篇Predator=prey cycles 答案详解
注意转折句子A new habitat , 本段主要讲的是predator 怎样影响prey 的数量，不是讲habitat.C.原文中没有比较D．未提，编造的A，逃脱C。
幸存D。
抵制B。
恢复，重新多起来本段重点注意however 之后的叙述，之前说的就是实验室研究表明在实验室环境下，首先predator 吃完所有prey, 然后自己饿死，但是，注意后面however的叙述，说的真实情况下，是prey 减少，predator减少，随后Prey 又rebound的故事。
所以还是要往However后面的内容上边来靠。
B。
原文未比较，C。
未提及实验的适应范围D。
未提及一些predator 也是其他动物的prey.A.会影响的B.没有完全消失，只是减少C.是hare 的大概人口循环周期，不是所有小不如动物的，偷换了概念根据排除法只能选D，另外结合第二段的内容，说到在现实条件中安全环境的情况下发生的事情，故还是选D。
高频词汇，同时经常与More or less 连用。
Generate =produceGeneration after generationChange =vary=modify=alternate=fluctuate=transformSpeed up=accelerateSmooth out=vi.弄平(消除)A.对应第一句话c. 对应2-3句d.对应最后一句B．未说过最高级的问题，而且high fiber 是不得已的选择最后一句话as…so …说明问题，当Hare数量下降的时候，Lynx的数量就下降，因为它的食物减少了。
B.说反，因果倒置C.说反D.说反，是相关的本段的逻辑关系可以由下图表示Hare food increase +no predator=hare increase and no cycle 排除A CCycle1=food 不变+no predatorCycle 2= food 增加+ 引入predator从而得出B是对的D没有说过hide 这个动词本段结构图可以如下画predator ---one species dominate and exclude other species1.no2.predator ===competitor controlled , some other species survived 证明A正确example,1.sea star---Bm---other organism can survive B 选项与此部分相反2. no sea star diversity decrease –one species will be eliminated C 选项与此部分相反D。
托福阅读事实信息题合集之TPO27-3(下)
托福阅读事实信息题合集之TPO27-3（下）托福阅读事实信息题是阅读考试中比较常见的一种题型，tpo则是托福阅读备考最权威的材料，所以托福小编综合二者，为大家集中整理了tpo阅读中考察的事实信息题及其对应的解析，供大家参考使用。
本文带来的是TPO27-3的事实信息题(下)，一起来看看吧。
TPO27-3 Predator-Prey CyclesParagraph 7:Predators are an essential factor in maintaining communities that are rich and diverse in species. Without predators, the species that is the best competitor for food, shelter, nesting sites, and other environmental resources tends to dominate and exclude the species with which it competes. ■This phenomenon is known as “competitor exclusion”. ■However, if the community contains a predator of the strongest competitor species, then the population of that competitor is controlled. ■Thus even the less competitive species are able to survive. ■For example, sea stars prey on a variety of bivalve mollusks and prevent these bivalves from monopolizing habitats on the sea floor. This opens up space for many other organisms. When sea stars are removed, species diversity falls sharply. Therefore, from the stand point of diversity, it is usually a mistake to eliminate a major predator from a community.11.According to paragraph 7, which of the following statements correctly characterizes the effect of sea stars on the ecosystem in which they are predators of bivalves?O Bivalve population are kept low, allowing species that compete with bivalves to survive.O The numbers of most species of bivalves are greatly reduced, leaving the bivalve species that is the strongest competitor to dominate among the survivors.O Biological diversity begins to decrease because many bivalve species disappear.O Sea stars dominate at first but then die off because of the depleted food supply.对应了原文这段倒数第二句和第三句。
托福TPO27口语Task3阅读文本+听力文本+题目+满分范文
托福TPO27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TPO27口语T ask3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TPO27口语Task3阅读文本：Switch to Electronic TextbooksThe university will begin switching from traditional-bound textbooks to electronic textbooks early next year. University students will be able to download the content of their required textbooks to a reading device and read the material directly from the device’s screen. While the cost of th e device is around $200, it is a one-time expense. Considering the rising cost of textbooks, students will save money in the long run since purchasing electronic books for their classes is much less expensive than buying regular textbooks. Furthermore, the university believes the device will be an effective study aid because it is simple to operate and offers features such as highlighting of text and note-taking.托福TPO27口语Task3听力文本：Now listen to two students discussing the article.(woman) Oh, no, did you see this?(man) Yeah, why? You don't like the idea?(woman) Not at all!(man) How come?(woman) Well, the cost, for one thing, they are just not being realistic.(man) Even compare to the price of textbooks?(woman) Well, sure, textbooks aren't cheap, but do you think people are only gonna use one device the whole time they are at university? What happens if yours breaks? You have to buy a newone. Or they come out with some fancy new features. Wouldn't you want to get a new one then?(man) Yeah, I see what you mean. A lot of people would probably want to replace theirs with the latest version.(woman) Right! Maybe even every year and that can add up.(man) True, but, don't you agree it'll make studying and preparing for classesa lot easier?(woman) I don't think everybody is gonna think it's so great.(man) What do you mean?(woman) Well., it's only helpful if it’s easy to use and, well, this thing is pretty small. It’s only about 18 or 20 centimeters tall.(man) Oh, really? So that means the screen’s prett y small.(woman) Right, and I heard that the key pad or control buttons, they are small, too. So if you have normal-sized fingers, it’s not so easy to select an item or get it to function right, you know, to do stuff like highlighting or underlining.(man) I hadn’t thought of that.(woman) So what good are all those fancy features if it’s hard to use them? Besides, I like the old-fashioned way of studying material: writing notes on the page and underlining or highlighting important sections of the book. I’m more comfortable with that. "托福TPO27口语Task3题目：The woman expresses her opinion about the university’s plan. Briefly summarize the plan, then state her opinion and explain the reasons she gives for holding that opinion.托福TPO27口语Task3满分范文：Well, according to the plan the university is to switch fromtraditional-bound textbooks to electronic textbooks early next year for two reasons. However the woman disagrees with the plan for several reasons. Firstly, she believes that it's not realistic for the cost issue since it'll still cost the students a lot when they break their devices or when they wish to get the devices upgraded for some new features they want. Besides, she thinks that the device itself is not practical too, because the screen is too small so it's difficult for even the normal-sized-fingered students to handle the key pad or buttons, letting alone selecting or underlining and stuff like that. Finally she personally favors the traditional way of studying material because she thinks it's more comfortable. All in all, the woman disagrees with the plan for the reasons stated above. (143 words)以上是给大家整理的托福TPO27口语T ask3阅读文本+听力文本+题目+满分范文，希望对你有所帮助!。
托福TPO27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TPO27阅读Passage3原文文本+题目+答案解析，希望对大家备考有所帮助。
Predator-Prey Cycles How do predators affect populations of the prey animals?The answer is not as simple as might be thought.Moose reached Isle Royale in Lake Superior by crossing over winter ice and multiplied freely there in isolation without predators.When wolves later reached the island,naturalists widely assumed that the wolves would play a key role in controlling the moose population.Careful studies have demonstrated,however,that this is not the case.The wolves eat mostly old or diseased animals that would not survive long anyway.In general,the moose population is controlled by food availability,disease and other factors rather than by wolves. 捕食者是怎样影响被捕食者的数量呢?答案并不是想象中那么简单。
麋鹿通过穿越冬天的冰层到达了在苏必略湖的罗亚尔岛，并由于没有捕食者而自由繁殖。
当狼在晚一点的时候到达那座岛时，自然学家都认为，狼对控制麋鹿的数量将起到关键作用。
老托福阅读试题及答案：PASSAGE27
老托福阅读试题及答案：PASSAGE27推荐文章老托福阅读真题及答案：PASSAGE30 热度：老托福阅读100篇passage33试题及答案热度：老托福阅读真题及答案：PASSAGE2 热度：托福阅读TPO14(试题+答案+译文)第1篇:儿童与广告热度：老托福阅读试题及答案：PASSAGE30 热度：为了帮助大家备考托福阅读，提高成绩，下面小编给大家带来老托福阅读真题及答案:passage 27，希望大家喜欢！老托福阅读试题及答案：PASSAGE 27The mineral particles found in soil range in size from microscopic clay particles to large boulders. The most abundant particles — sand, silt, and clay — are the focus of examination in studies of soil texture. Texture is the term used to describe the composite sizes of particles in a soil sample, typically several representative handfuls.To measure soil texture, the sand, silt, and clay particles are sorted out by size and weight. The weights of each size are then expressed as a percentage of the sample weight. In the field, soil texture can be estimated by extracting a handful of soil and squeezing the damp soil into three basic shapes; (1) cast, a lump formed by squeezing a sample in a clenched fist; (2) thread, a pencil shape formed by rolling soil between the palms; and (3) ribbon, a flatfish shape formed by squeezing a small sample between the thumb and index finger. The behavioral characteristics of the soil when molded into each of these shapes, if they can be formed at all, provide the basis for a general textural classification. The behavior of the soil in the hand test is determined by the amount of clay in the sample. Clay particles are highly cohesive, and when dampened, behave as a plastic.Therefore the higher the clay content in a sample, the more refined and durable the shapes into which it can be molded.Another method of determining soil texture involves the use of devices called sediment sieves, screens built with a specified mesh size. When the soil is filtered through a group of sieves, each with a different mesh size, the particles become grouped in corresponding size categories. Each category can be weighed to make a textural determination. Although sieves work well for silt, sand, and larger particles, they are not appropriate for clay particles. Clay is far too small to sieve accurately; therefore, in soils with a high proportion of clay, the fine particles are measured on the basis of their settling velocity when suspended in water. Since clays settle so slowly, they are easily segregated from sand and silt. The water can be drawn off and evaporated, leaving a residue of clay, which can be weighed.1. What does the passage mainly discuss?(A) Characteristics of high quality soil(B) Particles typically found in most soils(C) How a high clay content affects the texture of soil(D) Ways to determine the texture of soil2. The author mentions "several representative handfuls" in line 4 in order to show(A) the range of soil samples(B) the process by which soil is weighed(C) the requirements for an adequate soil sample(D) how small soil particles are weighted3. The phrase "sorted out" in line 5 is closest in meaning to(A) mixed(B) replaced(C) carried(D) separated4. It can be inferred that the names of the three basic shapes mentioned in paragraph 2 reflect(A) the way the soil is extracted(B) the results of squeezing the soil(C) the need to check more than one handful(D) the difficulty of forming different shapes5. The word "dampened" in line 14 is closest in meaning to(A) damaged(B) stretched(C) moistened(D) examined6. Which of the following can be inferred from the passage about a soil sample with little or no clay in it?(A) It is not very heavy.(B) It may not hold its shape when molded.(C) Its shape is durable(D) Its texture cannot be classified7. The word "they" in line 21 refers to(A) categories(B) sieves(C) larger particles(D) clay particles8. It can be inferred from the passage that the sediment sieve has an advantage over the hand test in determining soil texture because(A) using the sieve takes less time(B) the sieve can measure clay(C) less training is required to use the sieve(D) the sieve allows for a more exact measure9. During the procedure described in paragraph 3, when clay particles are placed into water they(A) stick to the sides of the water container(B) take some time to sink to the bottom(C) separate into different sizes(D) dissolve quickly10. The word "fine" in line 24 is closest in meaning to(A) tiny(B) many(C) excellent(D) various11. All of the following words are defined in the passage EXCEPT(A) texture (line 3)(B) ribbon (line 10)(C) sediment sieves (line 18)(D) evaporated (line 25)正确答案：DADBC BBDBA D托福阅读怎么练?有些考生则喜欢把文章一字不漏地细读之后再做题。
【威学教育】王鑫托福阅读TPO32-3阅读文本
【王鑫托福阅读】托福TPO全集之TPO32-3TPO32TPO32-3 Distributions of Tropical Bee Colonies1. The word “rival” in the passage is closest in meaning toA establishedB competingC nearbyD different2. According to paragraph 2, some species of stingless bees are aggressive mainly towardA nonaggressive bees that forage on the same flowersB aggressive bees of other speciesC bees from their own colonyD bees of their own species from different coloniesA3. According to paragraph 3, Hubbell and Johnson hypothesized thatA the distribution pattern of bee colonies determines the degree of aggressiveness the bees displayB nests of nonaggressive bees have either a random or a clumped distribution, while nests of aggressive bees have a regular distributionC nests of nonaggressive bees are generally both closer together and more regularly distributed than those of aggressive beesD nests of aggressive bees tend to be more regular in shape than those of nonaggressive beesIn 1977 ecologists Stephen Hubbell and Leslie Johnson recorded a dramatic example of how social interactions can produce and enforce regular spacing in a population. They studied competition and nest spacing in populations ofstingless bees in tropical dry forests in Costa Rica. Though these bees do no sting, rival colonies of some species fight fiercely over potential nesting sites.Stingless bees are abundant in tropical and subtropical environments, where they gather nectar and pollen from a wide variety of flowers. They generally nest in trees and live in colonies made up of hundreds to thousands of workers. Hubbell and Johnson observed that some species of stingless bees are highly aggressive to members of their species from other colonies, while other species are not. Aggressive species usually forage in groups and feed mainly on flowers that occur in high-density clumps. Nonaggressive species feed singly or in small groups and on more widely distributed flowers.Hubbell and Johnson studied several species of stingless bees to determine whether there is a relationship between aggressiveness and patterns of colony distribution. They predicted that the colonies of aggressive species would show regular distributions, while those of nonaggressive species would show random or closely grouped (clumped) distribution. They concentrated their studies on a thirteen-hectare tract of tropical dry forest that contained numerous nests of nine species of stingless bees.4. According to paragraph 4, why did Hubbell and Johnson begin their study by mapping all the potential nest sites?A To determine whether the availability of potential nest sites played a role in the distribution of bee coloniesB To know exactly where in the study area the coloniesof all the different bee species were locatedC To be sure that suitable nesting sites were equallyavailable in all parts of the study areaD To find out whether different species of beespreferred different types of trees as potential nestsites5. 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 The limited number of colonies was not due to the distribution or availability of potential nesting sites.B There was no lack of suitable trees or potential nesting sites in the study area.C The number of nests was directly related to the number or the distribution of suitable trees.D Neither the number nor the distribution of colonies could be explained by the availability of suitable nest sites.6. According to paragraph 5, Hubbell and Johnson determined A the order in which the colonies in the study area had been establishedB the level of aggressiveness of each of the nine speciesC the distribution pattern of the nests of five of the nine speciesD the number of colonies of each of the nine species7. Why does the author indicate that “The fifth species was not aggressive, and its nests were randomly distributed over the study area”?A To identify research results that contradicted Hubbell and Johnson's original hypothesisB To indicate that research results confirmed that nestThough Hubbell and Johnson were interested in how bee behavior might affect colony distributions, they recognized that the availability of potential nest sites for colonies could also affect distributions.So as one of the first steps in their study, they mapped the distributions of trees suitable for nesting. They found that potential nest trees were distributed randomly through the study area. They also found that the number of potential nest sites was muchgreater than the number of bee colonies. What did these measurements show the researchers? The number ofcoloniesinthe study area wasnotlimitedbyavailabilityof suitable trees, andaclumpedorregular distribution of colonies was not due toanunderlyingclumped or regulardistributionofpotential nest sites.Hubbell and Johnson mapped the nests of five of the nine species of stingless bees accurately, and the nests of four of these species were distributed regularly. All four species with regular nest distributions were highly aggressive to bees from other colonies of their own species. The fifth species was not aggressive, and its nests were randomly distributed over the study area.8. distribution was related to aggressiveness C To introduce the hypothesis that, within the same species, not all colonies are aggressive D To point out that both aggressive and nonaggressive species are equally successful at finding nest sitesThe phrase “insights into” in the passage is closest i n meaning to A tools to studyB opportunities forC evidence ofD an understanding of9. According to paragraph 6, what is one result of using pheromones to mark nest sites?A The use of pheromones tends to result in nest clumping.B Pheromones attract animals other than bees to prospective nest sites.C Pheromones tend to make bees aggressive.D Pheromones secreted by bees of one colony also attract bees of other colonies.10. The word “escalated” in the passage is closest in meaning toA intensifiedB transformedC combinedD lengthened11. Paragraph 7 supports which of the following ideas about fights over occupied nests?A They are more violent than battles over unoccupied nest sites.B They mostly occur between colonies of different species.C They are more frequent than battles over unoccupied sites.D They last longer than battles over unoccupied sites do.The researchers also studied the process by which the aggressive species establish new colonies. Their observations provide insights into the mechanisms that establish and maintain the regular nest distribution of these species. Aggressive species apparently mark prospective nest sites with pheromones, chemical substances secreted by some animals for communication with other members of their species. The pheromone secreted by these stingless bees attracts and aggregates members of their colony to the prospective nest site; however, it also attracts workers from other nests.If workers from two different colonies arrive at the prospective nest at the same time, they may fight for possession. Fights may be escalated into protracted battles.The researchers observed battles over a nest tree that lasted for two weeks. Each dawn, fifteen to thirty workers from two competing colonies arrived at the contested nest site. The workers from the two colonies faced off in two swarms and displayed and fought with each other. In the displays, pairs of bees faced each other, slowly flew vertically to a height of about three meters, and then grappled each other to the ground. When the two bees hit the ground, they separated, faced off, and performed another aerial display. Bees did not appear to be injured in these fights, which were apparently ritualized. The two swarms abandoned the battle at about 8 or 9 A.M. each morning, only to re-form and begin again the next day just afterdawn. While this contest over an unoccupied nest site produced no obvious mortality, fights over occupied nests sometimes kill over 1,000 bees in a single battle.Though Hubbell and Johnson were interested in how bee behavior might affect colony distributions, they recognized that the availability of potential nest sites for colonies could also affect distributions.(So as one of the first steps in their study, they mapped the distributions of trees suitable for nesting. (They found that potential nest trees were distributed randomly through the study area. (They also found that the number of potential nest sites was much greater than the number of bee colonies. (What did these measurements show the researchers? The number of colonies in the study area was not limited by availability of suitable trees, and a clumped or regular distribution of colonies was not due to an underlying clumped or regular distribution of potential nest sites.12. Look at the four squares [(] that indicate where the following sentence could be added to the passage. Where does the sentence best fit? For example, a clumped distribution of nests might simply reflect a clumped distribution of suitable nesting sites.13.Select from the seven sentences below the three sentences that correctly characterize aggressive species of stingless bees and the two sentences that correctly characterize nonaggressive species.Answer ChoicesA. Nests are regularly distributedB. Nests are sometimes located close togetherC. Nests always occur in large clumpsD. Colonies are generally made up of fewer than 100 workerE. Members of a colony feed alone or in small groupsF. Bees feed mainly on flowers that grow in high-density clumpsNest spacing is maintained by fighting。
托福TPO27综合写作阅读原文+听力原文+满分范文
¡¡¡¡ÎªÁË°ïÖú´ó¼Ò¸ßЧ±¸¿¼Íи££¬Îª´ó¼Ò´øÀ´Íи£TPO27×ÛºÏд×÷ÔĶÁÔ-ÎÄ+ÌýÁ¦Ô-ÎÄ+Âú·Ö·¶ÎÄ£¬Ï£Íû¶Ô´ó¼Ò±¸¿¼ÓÐËù°ïÖú¡£¡¡¡¡Íи£TPO27×ÛºÏд×÷ÔĶÁÔ-ÎÄÎı¾£º¡¡¡¡The little ice age was a period of unusually cold temperature in many parts of the world that lasted from about the year 1350 until 1900CE. There were unusually harsh winters, and glaciers grew larger in many areas. Scientist have long wondered what caused the Little Ice Age. Several possible causes have been proposed. First, the cooling may have been caused by disrupting of ocean currents. Before the Little Ice Age, there was a period of unusually warm weather during which glaciers melted. These melted glaciers sent a large amount of cold freshwater into the Gulf Stream, a large ocean current that strongly affects Earth's climate. Some scientists believe that this freshwater was enough to temporarily disrupt the Gulf Stream. Such a disruption could have caused the Little Ice Age. Second, volcanic eruption could have caused the Little Ice Age. When volcanoes erupt, they send dark clouds of dust and sulfur gas into the atmosphere. These clouds, which can spread over great areas, block some sunlight from reaching Earth's surface. This can decrease the global temperatures. Scientists know of several volcanic eruption that took place during the Little Ice Age. Third, substantial decreases in human populations may have contributed indirectly to the cooling of the climate. For a variety of reason(disease, warfare, social disruption), the human population just before the Little Ice Age and during the early part of it was lower than it had been in a long time. Forest trees started growing on fields that were no longer used for agriculture. Since trees absorb carbon dioxide, a greenhouse gas, they decrease the greenhouse effect that keeps Earth warm. With more forest trees carbon dioxide, earth became cooler.¡¡¡¡Íи£TPO27×ÛºÏд×÷ÌýÁ¦Ô-ÎÄÎı¾£º¡¡¡¡Unfortunately, the arguments of the reading passage are a little out of date. Scientists now have new information that shows that none of the ideas the reading passage discusses could account for the Little Ice Age.First, about the Gulf Stream. Scientists now know that disrupting the Gulf Stream would cause cooling only in Europe and North America, but the Little Ice Age also affected the Southern hemisphere, in places like New Zealand and Southern Africa for example. Since the disruption of the Gulf Stream cannot explain why these southern areas became colder, it cannot explain the Little Ice Age.Second, the volcanoes theory. It's true that if volcanic eruptions put enough dust into the atmosphere the result can be a cooler climate. But large amounts of volcanic dust in the atmosphere would have also produced striking visual effect that people would have noticed at the time, for example, dramatically colorful Sunsets or snow being grey or brown instead of white. But there are almost no reports of anything like that routinely happening during the Little Ice Age. So it seems that the volcanic eruptions during that period were simply not strong enough to release the large amounts of dust needed to lower global temperatures.Third, about forestson farmland stopping the warming greenhouse effect by removing carbon dioxide. There just was not enough time for this effect to work. The human population grew back to previous levels fairly quickly, which meant that forests were soon being cut down again to clear fields for the crops needed to fed the growing population. As a result, we know that the forests mentioned in the reading passage were not there long enough to cause the long¡ªterm global cooling of the climate.¡¡¡¡Íи£TPO27×ÛºÏд×÷Âú·Ö·¶ÎÄ1£º¡¡¡¡In the reading passage, the author claims that the cause of the Little Ice Age was due to three main reasons. The lecturer, however, reputes the writer¡¯s opinion one by one with strong arguments. Firstly, the passage argues that the Gulf Stream formed in the previous warm period was responsible for the appearance of the unexpected Little Ice Age. Yet, the speaker argues that the so-called Gulf Stream only contributed to the cooling weather in Northern hemisphere while Little Ice Age took place all over the world. Thus, global Little Ice Age cannot be Next, according to the reading material, dust and sulfur gas caused by volcanic eruptions would block sunlight, and resulted in Little Ice Age. he lecturer, however, holds that volcanic eruptions should have led to other visual phenomena than cooling weather, like colorful sunsets or grey snow. But unfortunately none of them were reported. Once taken this into consideration, volcanic eruptions seems not strong enough to release the large amounts of dusts needed to lower global temperatures. Last but not least, the writer states that the substantial decrease in human population may cause the unusual Little Ice Age. Again the speaker argues.¡¡¡¡Íи£TPO27×ÛºÏд×÷Âú·Ö·¶ÎÄ2£º¡¡¡¡The reading passage proposes 3 possible causes of little ice age, but all the explanations are refuted by the professor in the lecture. F irst, according to the reading passage, the disruption of Gulf Stream may have caused the little ice age. However, in the lecture, the professor argues that the disruption can only effect Europe and North America. But the ice age also effected south hemisphere like New Zealand and South Africa. Since the disruption cannot explain why it get cooler in south hemisphere, it cannot fully explain the little ice age. S econd, the professor also refutes the reading passage that volcano caused the ice age. As the professor puts, large amount of dust produced by volcano would have produced striking visual effect that people would have noticed at that time, such as colorful sunsets. Since there are no reports of such visual effects at the time, the volcanic eruptions during that period were not strong enough to cause ice age. Third, contrary to the reading that due to human population decrease, the growth of forest trees contributed to little ice age by removing carbon dioxide, the professor points out that there is not enough time for this effect to work. The professor argues that the human population grew back quickly to the previous level and lots of trees were cut down for the crops to feed the growing population. Therefore, there is not enough time for the forest to。
【威学教育王鑫整理出品】托福TPO7-3阅读文本
【王鑫托福阅读】托福TPO7-3阅读文本TPO7TPO7-3 Agriculture Iron and the Bantu Peoplesng this time1. The word “diffused” in the passage is closest in meaning toA. emergedB. was understoodC. spreadD. developed2. According to paragraph 1, why do researchers doubt that agriculture developed independently in Africa?A. African lakes and rivers already provided enough food for people to survive without agriculture.B. The earliest examples of cultivated plants discovered in Africa are native to Asia.C. Africa ’ s native plants are very difficult to domesticate.D. African communities were not large enough to support agriculture.3.In paragraph 1, what does the author imply about changes in the African environment during period?A. The climate was becoming milder, allowing for a greater variety of crops to be grown.B. Although periods of drying forced people south, they returned once their food supply was secure.C. Population growth along rivers and lakes was dramatically decreasing the availability of fish.D. A region that had once supported many people was becoming a desert where few could survive.There is evidence of agriculture in Africa prior to 3000B. C. It may have developed independently, but many scholars believe that the spread of agriculture and iron throughout Africa linked it to the major centers of the Near East and Mediterranean world. The drying up of what is now the Sahara desert had pushed many peoples to the south into sub-Sahara Africa. These peoples settled at first in scattered hunting-and-gathering bands, a lt hough in some places near lakes and rivers, people who fished, with a more secure food supply, lived in larger population concentrations. Agriculture seems to have reached these people from the Near East, since the first domesticated crops were millets and sorghums whose origins are not African but west Asian. Once the idea of planting diffused, Africans began to develop their own crops, such as certain varieties of rice, and they demonstrated a continued receptiveness to new imports. The proposed areas of the domestication of Afri can crops lie in a band that extends from Ethiopia across southern Sudan to West Africa. Subsequently, other crops, such as bananas, were introduced from Southeast Asia.4. According to paragraph 2, camels were important because theyA. were the first domesticated animal to be introduced to AfricaB. allowed the people of the West African savannahs to carve out large empiresC. helped African peoples defend themselves against Egyptian invadersD. made it cheaper and easier to cross the Sahara5. According to paragraph 2, which of the following were subjects of rock paintings in the Sahara?A. Horses and chariotsB. Sheep and goatsC. Hyksos invaders from EgyptD. Camels and cattle6. What function does paragraph 3 serve in the organization of the passage as a whole?A. It contrasts the development of iron technology in West Asia and West Africa.B. It discusses a non-agricultural contribution to Africa from Asia.C. It introduces evidence that a knowledge of copper working reached Africa and Europe at the same time.D. It compares the rates at which iron technology developed in different parts of Africa7. The word “profound” in the passage is closest in meaning toA. fascinatingB. far-reachingC. necessaryD. temporaryLivestock also came from outside Africa. Cattle were introduced from Asia, as probably were domestic sheep and goats. Horses were apparently introduced by the Hyksos invaders of Egypt (1780-1560 B.C.) and then spread across the Sudan to West Africa. Rock paintings in the Sahara indicate that horses and chariots were used to traverse the desert and that by 300-200 B.C., there were trade routes across the Sahara. Horses were adopted by peoples of the West African savannah, and later their powerful cavalry forces allowed them to carve out large empires. Finally, the camel was introduced around the first century A.D. This was an important innovation, because the camel’ s abilities to thrive in harsh desert conditions and to carry large loads cheaply made it an effective and efficient means of transportation. The camel transformed the desert from a barrier into a still difficult, but more accessible, route of trade and communication.Iron came from West Asia, although its routes of diffusion were somewhat different than those of agriculture. Most of Africa presents a curious case in which societies moved directly from a technology of stone to iron without passing through the intermediate stage of copper or bronze metallurgy, although some early copper-working sites have been found in West Africa. Knowledge of iron making penetrated into the forest and savannahs of West Africa at roughly the same time that iron making was reaching Europe. Evidence of iron making has been found in Nigeria, Ghana, and Mali.This technological shift cause profound changes in the complexity of African societies. Iron represented power. In West Africa the blacksmith who made tools and weapons had an important place in society, often with special religious powers and functions. Iron hoes, which made the land more productive, and iron weapons, which made the warrior more powerful, had symbolic meaning in a number of West Africa societies. Those who knew the secrets of making iron gained ritual and sometimes political power.8. The word “ritual” in the passage is closest in meanin g toA. militaryB. physicalC. ceremonialD. permanent9. According to paragraph 4, all of the following were social effects of the new metal technology in Africa EXCEPT:A. Access to metal tools and weapons created greater social equality.B. Metal weapons increased the power of warriors.C. Iron tools helped increase the food supply.D. Technica丨 knowledge gave religious power to its holders.10. 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. While American iron makers developed the latest furnaces, African iron makers continued using earlier techniques.B. Africans produced iron much earlier than Americans, inventing technologically sophisticated heating systems.C. Iron making developed earlier in Africa than in the Americas because of the ready availability of carbon and iron ore.D. Both Africa and the Americas developed the capacity for making iron early, but African metallurgy developed at a slower rate.Unlike in the Americas, where metallurgy was a very late and limited development, Africans had iron from a relatively early date, developing ingenious furnaces to produce the high heat needed for production and to control the amount of air that reached the carbon and iron ore necessary for making iron. Much of Africa moved right into the Iron Age, taking the basic technology and adapting it to local conditions and resources.11. The word “fleeing” in the passage is closest in meaning toA. afraid ofB. displaced byC. running away fromD. responding to12. Paragraph 6 mentions all of the following as possible causes of the “ Bantu explosion ” EXCEPTA. superior weaponsB. better hunting skillsC. peaceful migrationD. increased populationThe diffusion of agriculture and later of iron was accompanied by a great movement of people who may have carried these innovations. These people probably originated in eastern Nigeria. Their migration may have been set in motion by an increase in population caused by a movement of peoples fleeing the desiccation, or drying up, of the Sahara. They spoke a language,proto-Bantu (“Bantu” means “the people” ), wh ich is the parent tongue of a language of a large number of Bantu languages still spoken throughout sub-Sahara Africa. Why and how these people spread out into central and southern Africa remains a mystery, but archaeologists believe that their iron weapons allowed them to conquer their hunting-gathering opponents, who still used stone implements. Still, the process is uncertain, and peaceful migration — or simply rapid demographic growth—may have also caused the Bantu explosion.The diffusion of agriculture and later of iron was accompanied by a great movement of people who may havecarried these innovations. These people probably originated in eastern Nigeria. (Their migration may have beenset in motion by an increase in population caused by a movement of peoples fleeing the desiccation, or drying up,of the Sahara. (They spoke a language, proto-Bantu (“Bantu” means “the people，，)，which is the parent tongueof a language of a large number of Bantu languages still spoken throughout sub-Sahara Africa. Why and how these people spread out into central and southern Africa remains a mystery, but archaeologists believe that their ironweapons allowed them to conquer their hunting-gathering opponents, who still used stone implements. (Still,the process is uncertain, and peaceful migration—or simply rapid demographic growth—may have also causedthe Bantu explosion.(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 people had a significant linguistic impact on the continent as well.14. Direction: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points. Agriculture and iron working probably spread to Africa from neighboring regions.A. Once Africans developed their own crops, they no longer borrowed from other regions.B. The harshness of the African climate meant that agriculture could not develop until after the introduction of iron tools.C. The use of livestock improved transportation and trade and allowed for new forms of political control.D. As the Sahara expanded, the camel gained in importance, eventually coming to have religious significance.E. The spread of iron working had far-reaching effects on social, economic, and political organization in Africa.F. Today's Bantu-speaking peoples are descended from a technologically advanced people who spread throughout Africa.。
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【王鑫托福阅读】托福TPO 全集之TPO27-3TPO 27TPO27-3 Predator Prey Cycles1. In paragraph 1, why does the author discuss the moose and wolves on Isle Royale?A To provide an example of predators moving to new habitats by following migrating preyB To show that the interactions between predator populations and prey populations are not always might be expectedC To suggest that prey populations are more influenced by predation than food availability and diseaseD To argue that studies of geographically isolated populations tend not to be useful to naturalists2. The word “rebound” in the passage is closest in meaning to A escapeB recoverC surviveD resist3. Paragraph 2 implies which of the following about experimental environments in which predators become extinct?A They may yield results that do not accurate predict changes of populations in the wild.B In these environments, the prey species is better adapted than the predator species.C These environments are appropriate only for studying small populations of predators and prey.D They are unrealistic because some predators are also the prey of other predators.4. Which of the following can be inferred from paragraphs 2 and 3 about the small mammals that experience population cycles? A Their population cycles are not affected by predators.B Their predators' populations periodically disappear.C They typically undergo ten-year cycles.D They have access to places safe from predators.How do predators affect populations of the prey animals? The answer is not as simple as might be thought. Moose reached Isle Royale in Lake Superior by crossing over winter ice and multiplied freely there in isolation without predators. When wolves later reached the island, naturalists widely assumed that the wolves would play a key role in controlling the moose population. Careful studies have demonstrated, however, that this is not the case. The wolves eat mostly old or diseased animals that would not survive long anyway. In general, the moose population is controlled by food availability, disease and other factors rather than by wolves.When experimental populations are set up under simple laboratory conditions, the predator often exterminates its prey and then becomes extinct itself, having nothing left to eat. However, if safe areas like those prey animals have in the wild are provided, the prey population drops to low level but not extinction. Low prey population levels then provide inadequate food for the predators, causing the predator population to decrease. When this occurs, the prey population can rebound. In this situation the predator and prey population may continue in this cyclical pattern for some time.Population cycles are characteristic of small mammals, and they sometimes appear to be brought about by predators. Ecologists studying hare populations have found that the North American snow shoe hare follows a roughly ten-year cycle. Its numbers fall tenfold to thirty in a typical cycle, and a hundredfold change can occur. Two factors appear to be generating the cycle: food plants and predators.5. The word “roughly” in the passage is closest in meaning toA usuallyB repeatingC approximatelyD observable6. The word “generating” in the passage is closest in meaning toA producingB changingC speeding upD smoothing out7. to paragraph 4, all of the following are true of the food of snowshoe hares EXCEPT A The preferred food fore hares consists of willow and birch twigs.B High fiber food is the most nutritious for hares.C Depletion of the supply of willow and birch twigs cause low birth and growth rates.D The food supply takes two or three years to recover8. The word “conjunction” in the passage is closest in meaning to A determinationB combinationC alternationD transformation9. According to paragraph 5, which of the following statements best characterizes the abundance cycle of the Canada lynx?A It closely follows the cycle the snowshoe hare.B When the numbers of lynx fall, the numbers of snowshoe hares soon decrease.The preferred foods of snowshoe hares are willow and birch twigs. As hare density increases, the quantity of these twigs decreases, forcing the hares to feed on low-quality high-fiber food. Lower birth rates, low juvenile survivorship, and low growth rates follow, so there is a corresponding decline in hare abundance. Once the hare population has declined, it takes two to three year for the quantity of twigs to recover.A key predator of the snowshoe hare is the Canada lynx. The Canada lynx shows a ten-year cycle of abundance that parallels the abundance cycle of hares. As hare numbers fall, so do lynx numbers, as their food supply depleted.What causes the predator-prey oscillations? Do increasing number of hares lead to overharvesting of plants, which in turn results in reduced hare populations, or do increasing numbers of lynx lead to overharvesting hares? Field experiments carried out by Charles Krebs and coworkers in 1992 provide an answer. Krebs investigated experimental plots in Canada's Yukon territory that contained hare populations. When food was added to those plots (no food effect) and predators were excluded (no predator effect) from an experimental area, hare numbers increased tenfold and stayed there—the cycle was lost. However, the cycle was retained if either of the factorsC When hare numbers decrease, lynx numbers increase.D It is not clearly related to the availability of lynx food.10. According to paragraph 6, which of the following was true of the hare population cycle in Krebs's experiment?A The effects of providing food while at the same time introducing predators cancelled each other, so there was no cycle.B The cycle existed when either the food supply was limited or there were predators.C There was a cycle when there were no predators and food was supplied.D If the hares had places to hide from the lynx, the hare population increased tenfold and then remained at that level.11. According to paragraph 7, which of the following statements correctly characterizes the effect of sea stars on the ecosystem in which they are predators of bivalves?A Bivalve population are kept low, allowing species that compete with bivalves to survive.B The numbers of most species of bivalves are greatly reduced, leaving the bivalve species that is the strongest competitor to dominate among the survivors.C Biological diversity begins to decrease because many bivalve species disappear.D Sea stars dominate at first but then die off because of the depleted food supply.12. According to paragraph 7, which of the following is true of the phenomenon of competitor exclusion?A It results in more diverse communities.B It requires the presence of predators.C It affects all competitions equally.D It happens only when there is a dominant competitor.was allowed to operate alone: if predators were excluded but food was not added (food effect alone), or if food was added in the presence of predators (predator effect alone). Thus both factors can affect the cycle, which, in practice, seems to be generated by conjunction of the two factors.K作义/ 产Predators are an essential factor in maintaining communities that are rich and diverse in species. Without predators, the species that is the best competitor for food, shelter, nesting sites, and other environmental resources tends to dominate and exclude the species with which it competes. This phenomenon is known as “competitor exclusion”. However, i f the community contains a predator of the strongest competitor species, then the population of that competitor is controlled. Thus even the less competitive species are able to survive. For example, sea stars prey on a variety of bivalve mollusks and prevent these bivalves from monopolizing habitats on the sea floor. This opens up space for many other organisms. When sea stars are removed, speciesdiversity falls sharply. Therefore, from the stand point of diversity, it is usually a mistake to eliminate a major predator from a community.Predators are an essential factor in maintaining communities that are rich and diverse in species. Without predators, the species that is the best competitor for food, shelter, nesting sites, and other environmental resources tends to dominate and exclude the species with which it competes. (This phenomenon is known as “competitor exclusion”. (However, if the community contains a predator of the strongest competitor species, then the population of that competitor is controlled. (Thus even the less competitive species are able to survive. (For example, sea stars prey on a variety of bivalve mollusks and prevent these bivalves from monopolizing habitats on the sea floor. This opens up space for many other organisms. When sea stars are removed, species diversity falls sharply. Therefore, from the stand point of diversity, it is usually a mistake to eliminate a major predator from a community.13. Look at the four squares [(] that indicate where the following sentence could be added to the passage. Where would the sentence best fit?As a result, there are not enough of the strong competitions to monopolize the environment’ s resources.14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points. The relationships between predators and prey are complex.A. Studies of the interactions between wolves and moose on Isle Royale in Lake Superior reveal that wolf predation is not the primary factor controlling the moose population.B. Ecologists are interested in studying predator-prey population cycles because understanding how predators and prey interact will allow better wildlife management programs.C. Predators help maintain biological diversity by limiting populations of a dominant competitor species, thereby preventing that species from excluding others.D. In predator-prey population cycles, predator populations increase or decrease following similar population changes in the species they prey on.E. A species’ population tends to rise and falls in a cycle pattern if the food supply for the population is limited, or if the population has a major predator.F. The removal of sea stars reduces the diversity of the community in which they are predators, and is therefore a bad idea.。