做GRE阅读理解真题时不能一味追求速度与数量，而应细心雕琢。下面无忧小编为大家整理了高质量新GRE阅读机经，希望可以帮助各位考生打开阅读思路，提高新GRE阅读能力。
8.玛雅文明
V1说某种果树在玛雅废墟那块,长得很好,这个是玛雅文明的证明,但是有人反对,说是因为蝙蝠吃了果子排出种子才造成了这片果树林,和玛雅没有关系...但是后面又有证明说这片果林的产量是其他地方的果林的产量的2倍,说明还是玛雅文明的影响.
V2考古玛雅文明 说是什么玛雅人有什么珍贵的东西 但是后来证明这些东西是后人放的;但是最后又说和玛雅文明有关系。 感觉挺难的
V3 Maya遗址North和South地区在不同时间消失的原因，文章中貌似提到和South地区的地势更高，难以获取地下水有关;(好像托福文章)
Maya Water Problems
To understand the ancient Mayan people who lived in the area that is today southern Mexico and Central America and the ecological difficulties they faced, one must first consider their environment, which we think of as “jungle" or 'tropical rainforest." This view is inaccurate, and the reason proves to be important. Properly speaking, tropical rainforests grow in high-rainfall equatorial areas that remain wet or humid all year round. But the Maya homeland lies more than sixteen hundred kilometers from the equator, at latitudes 17 to 22 degrees north, in a habitat termed a “seasonal tropical forest." That is, while there does tend to be a rainy season from May to October, there is also a dry season from January through April. If one focuses on the wet months, one calls the Maya homeland a "seasonal tropical forest"; if one focuses on the dry months, one could instead describe it as a "seasonal desert.”
From north to south in the Yucatan Peninsula, where the Maya lived, rainfall ranges from 18 to 100 inches (457 to 2,540 millimeters) per year, and the soils become thicker, so that the southern peninsula was agriculturally more productive and supported denser populations. But rainfall in the Maya homeland is unpredictably variable between years; some recent years have had three or four times more rain than other years. As a result, modern farmers attempting to grow corn in the ancient Maya homelands have faced frequent crop failures, especially in the north. The ancient Maya were presumably more experienced and did better, but nevertheless they too must have faced risks of crop failures from droughts and hurricanes.
Although southem Maya areas received more rainfall than northern areas, problems of water were paradoxically more severe in the wet south. While that made things hard for ancient Maya living in the south, it has also made things hard for modem archaeologists who have difficulty understanding why ancient droughts caused bigger problems in the wet south than in the dry north. The likely explanation is that an area of underground freshwater underlies the Yucatan Peninsula, but surface elevation increases from north to south, so that as one moves south the land surface lies increasingly higher above the water table. In the northern peninsula the elevation is sufficiently low that the ancient Maya were able to reach the water table at deep sinkholes called cenotes, or at deep caves. In low-elevation north coastal areas without sinkholes, the Maya would have been able to get down to the water table by digging wells up to 75 feet (22 meters) deep. But much of the south lies too high above the water table for cenotes or wells to reach down to it. Making matters worse, most of the Yucatan Peninsula consists of karst, a porous sponge-like limestone terrain where rain runs straight into the ground and where little or no surface water remains available.
How did those dense southern Maya populations deal with the resulting water problem? It initially surprises us that many of their cities were not built next to the rivers but instead on high terrain in rolling uplands. The explanation is that the Maya excavated depressions, or modified natural depressions, and then plugged up leaks in the karst by plastering the bottoms of the depressions in order to create reservoirs, which collected rain from large plastered catchment basins and stored it for use in the dry season.For example, reservoirs at the Maya city of Tikal held enough water to meet the drinking water needs of about 10,000 people for a period of 18 months. At the city of Coba the Maya built dikes around a lake in order to raise its level and make their water supply more reliable. But the inhabitants of Tikal and other cities dependent on reservoirs for drinking water would still have been in deep trouble if 18 months passed without rain in a prolonged drought. A shorter drought in which they exhausted their stored food supplies might already have gotten them in deep trouble, because growing crops required rain rather than reservoirs.
9. 鹿背上的hamp(逻辑单题)
现有化石无法确定古代的一种鹿背上是不是humped。后来考古学家发现了一个洞窟里图片画了有hump的鹿，那么考虑到XXXX unmistakable，这是可信的。后来又说有人质疑这个画只是为了某种仪式ritual画的，不一定真实。但这是不足以担忧的，因为考古学家们发现洞里的其他画都非常写实。问的是这个提到XXXX unmistakable，和后面的这个洞里的其他画都写实分别有什么用，四个选项都是说的这两个句子用途不一样，而E是说他们都是结论conclusion的证据。我选的E。
Which of following most logically completes the argument?
The last members of a now-extinct species of a European wild deer called the giant dear lived in Ireland about 16,000 years ago. Prehistoric cave paintings in France depict this animal as having a large hump on its back. Fossils of this animal, however, do not show any hump. Nevertheless, there is no reason to conclude that the cave paintings are therefore inaccurate in this regard, since ______.
A some prehistoric cave paintings in France also depict other animals as having a hump
B fossils of the giant deer are much more common in Ireland than in France
C animal humps are composed of fatty tissue, which dose not fossilize
D the cave paintings of the giant deer were painted well before 16,000 years ago
E only one currently existing species of deer has any anatomical feature that even remotely resembles a hump
10. Mystery of the Anasazi."
即使XXXX，某些人抛弃了XXX Mesa还是很puzzling.后来人们发现一种maize在人们住在这个mesa的后期变得很少，看来是食物原因。而且后来人们发现在这个后期一种喂养的火鸡的食用量55降到14，而野生动物食用增加。一开始我没留意到wild plant和wild animal的区别，题目都看晕。后来发现第一段讲的是crop第二段讲的是动物ORZ。
As the tourists prepare to depart Spruce Tree House, one asks Qumawunu the question that's on everyone's mind: Why, after having invested so much work in this place, did the ancestral Pueblo people leave it all behind?
The park ranger's answer sounds well-rehearsed: "We can come up with so many thoughts about why they moved in and why they moved out. But no one really knows for sure."
But it's a mystery that is finally beginning to unravel.
But while Crow Canyon has brought professional archaeology to the masses, it has yet to dismantle the biggest misconception about Mesa Verde's prehistory: that the ancestral Pueblo people simply vanished.
"I don't think we really ever thought that they just vanished into thin air," says Kuckelman. "I think the real enigma of the ancestral Pueblo people in the Mesa Verde region is, ŒWhy did they leave?'"
The ancestral Pueblo people didn't have a written language; no one left behind a detailed account of their last days in the Mesa Verde region. But Kuckelman believes that if she looks hard enough at places like Goodman Point Pueblo, she can find this story written on the walls -- and on the floors and in the trash heaps.
There's a partially excavated kiva, a subterranean dwelling near the northwest corner, that could hold part of the story. Standing over it, Kuckelman lifts the plywood covering that will protect the underground chamber over the winter and peers into the darkness. When this kiva was first excavated last summer, workers discovered prehistoric ash in the hearth and a rabbit skeleton nearby. Kuckelman thinks those findings may be the remains of one of the last meals ever eaten in the village.
She believes that when researchers dissolve the ash in liquid and analyze what remains, they'll find markedly little evidence of maize, compared to the amount of maize refuse in rubbish pits around the village. This isn't a wild guess. Kuckelman and her co-workers noticed the pattern when they ran similar tests at a nearby contemporary ruin, Sand Canyon Pueblo. These findings helped Kuckelman piece together a new theory about the ancestral Pueblo's departure, a theory she hopes to bolster with evidence from Goodman Point Pueblo and other excavations.
Kuckelman believes that as more and more people settled in the Mesa Verde region in the thirteenth century, they overwhelmed wild food sources in the area, such as deer and wild plants. As a result, they became increasingly dependent on maize crops -- not just for food, but for feed for domesticated turkeys -- as evidenced by the ubiquity of maize in refuse pits, essentially time capsules of the villagers' eating habits and customs. But then something wiped out their ability to cultivate their crops, as indicated by the limited maize remains in hearths. The rabbit skeleton may also be a clue, suggesting that turkey populations may have died out and forced these people to fall back on small wild game. This could mean that Kuckelman has found more than just evidence of the last meals ever eaten by the ancestral Pueblo people in the Mesa Verde region; she's found a possible impetus for their leaving: to search out new means of sustenance.
"The folks in this area had become very, very dependent on crops, like maize, and wild turkeys. Ultimately, I think that system backfired and collapsed on them," she says.
But why did the system backfire? Why did the entire population collapse? For a while, archaeologists thought they had the single answer: a great drought.
This idea was born from ancient wooden beams found in Mesa Verde ruins, beams whose tree rings captured the exact date and climate conditions of the prehistoric time period. Andrew E. Douglass, the father of tree-ring dating, studied these beams and, in a 1929 National Geographic article evocatively titled "The Secret of the Southwest Solved by Talkative Tree-rings," announced that he'd cleared up the mystery of the prehistoric migration. The beams, he wrote, showed evidence of a massive drought in the region from 1276 to 1299. Drought can be apocalyptic in the Mesa Verde region -- soil turns to powder, trees hold less moisture than kiln-dried wood -- and this one, it seemed, had led to a mass exodus.
Scholars are skeptical of single-factor explanations. Could one drought, no matter how devastating, be enough to depopulate an entire region? But for decades, no one had the hard evidence to challenge the drought theory. "Interpretations were kind of all over the board," says Kuckelman. That changed seventeen years ago, thanks to the work of a Ph.D. student named Carla Van West.
11. 彗星的pristine relics
关于宇宙里一些彗星的pristine relics, 新的研究表明因为接近太阳时温度太高，里面的relics很难测定。
The long-held perspective that comets are pristine remnants from the formation of the solar system has evolved from the prevailing views of 30 years ago, finds planetary scientist Dr. S. Alan Stern in a paper published in the journal Nature.
"It's fair to say that a sea change has taken place," says Stern, director of the Space Studies Department in the SwRI Space Science and Engineering Division. "We used to consider comets as wholly unchanged relics that had been stored ever since the era of solar system formation in a distant, cold, timeless deep freeze called the Oort cloud. We now appreciate that a variety of processes slowly modify comets during their storage there," he says. "As a result, it's become clear that the Oort cloud and its cousin the Kuiper Belt are not such perfect deep freezes."
The first evolutionary process to be recognized as affecting comets during their long storage was radiation damage, followed by the discovery that sandblasting from dust grains in the interstellar medium plays an important role. Next, researchers theorized that comets in the Oort cloud are heated to scientifically significant temperatures by passing stars and supernovae, says Stern. More recently, researchers are finding that comets in the Kuiper Belt are heavily damaged by collisions.
"It also now seems inevitable that most comets from the Kuiper Belt, though constructed of ancient material, cannot themselves be ancient -- instead they must be 'recently' created chips off larger Kuiper Belt Objects, formed as a result of violent impacts," says Stern. "This is truly a paradigm shift. Many of the short-period comets we see aren't even ancient!"
The classical view that comets do not evolve while they are stored far from the sun in the Oort cloud and Kuiper Belt began to change as far back as the 1970s, but the pace of discoveries about the way comets evolve picked up considerably in the 1980s and 1990s.
As a result of these findings, astronomers now better appreciate that comets, though still the most pristine bodies known, have been modified in several important ways since their birth, says Stern.
The realization that comets evolve during their long storage in the Oort cloud and Kuiper Belt provides insight and context to more confidently evaluate the results of astronomical and space mission observations of comets. So, too, it suggests that cometary sample return missions now on the drawing board for NASA should employ relatively deep subsurface sampling if truly pristine, ancient material is to be collected.
12.法国二月革命(原题)
In February 1848 the people of Paris rose in revolt against the constitutional monarchy of Louis-Philippe. Despite the existence of excellent narrative accounts, the February Days, as this revolt is called, have been largely ignored by social historians of the past two decades. For each of the three other major insurrections in nineteenth-century Paris—July 1830, June 1848, and May 1871—there exists at least a sketch of participants’ backgrounds and an analysis, more or less rigorous, of the reasons for the occurrence of the uprisings. Only in the case of the February Revolution do we lack a useful description of participants that might characterize it in the light of what social history has taught us about the process of revolutionary mobilization.
Two reasons for this relative neglect seem obvious. First, the insurrection of February has been overshadowed by that of June. The February Revolution overthrew a regime, to be sure, but met with so little resistance that it failed to generate any real sense of historical drama. Its successor, on the other hand, appeared to pit key socioeconomic groups in a life-or-death struggle and was widely seen by contemporary observers as marking a historical departure. Through their interpretations, which exert a continuing influence on our understanding of the revolutionary process, the impact of the events of June has been magnified, while, as an unintended consequence, the significance of the February insurrection has been diminished. Second, like other “successful” insurrections, the events of February failed to generate the most desirable kinds of historical records. Although the June insurrection of 1848 and the Paris Commune of 1871 would be considered watersheds of nineteenth-century French history by any standard, they also present the social historian with a signal advantage: these failed insurrections created a mass of invaluable documentation as a by-product of authorities’ efforts to search out and punish the rebels.
Quite different is the outcome of successful insurrections like those of July 1830 and February 1848. Experiences are retold, but participants typically resume their daily routines without ever recording their activities. Those who played salient roles may become the objects of highly embellished verbal accounts or in rare cases, of celebratory articles in contemporary periodicals. And it is true that the publicly acknowledged leaders of an uprising frequently write memoirs. However, such documents are likely to be highly unreliable, unrepresentative, and unsystematically preserved, especially when compared to the detailed judicial dossiers prepared for everyone arrested following a failed insurrection. As a consequence, it may prove difficult or impossible to establish for a successful revolution a comprehensive and trustworthy picture of those who participated, or to answer even the most basic questions one might pose concerning the social origins of the insurgents.
17. According to the passage, “a useful description of participants” (lines 11-12) exists for which of the following insurrections of nineteenth-century France?
I. The July Insurrection of 1830
II. The February Revolution of 1848
III. The June insurrection of 1848
IV. The May insurrection of 1871
(A) I and III only
(B) II and IV only
(C) I, II, and III only
(D) I, III, and IV only
(E) II, III, and IV only
18. It can be inferred from the passage that support for the objectives of the February Revolution was
(A) negligible
(B) misguided
(C) fanatical
(D) spontaneous
(E) widespread
19. Which of the following, best describes the organization of the second paragraph?
(A) The thesis of the passage is stated and supporting evidence systematically presented.
(B) Two views regarding the thesis presented in the first paragraph are compared and contrasted.
(C) Evidence refuting the thesis presented in the first paragraph is systematically presented.
(D) The thesis presented in the first paragraph is systematically supported.
(E) The thesis presented in the first paragraph is further defined and a conclusion drawn.
20. It can be inferred from the passage that the author considers which of the following essential for understanding a revolutionary mobilization?
(A) A comprehensive theory of revolution that can be applied to the major insurrections of the nineteenth century
(B) Awareness of the events necessary for a revolution to be successful
(C) Access to narratives and memoirs written by eyewitnesses of a given revolution
(D) The historical perspective provided by the passage of a considerable amount of time
(E) Knowledge of the socioeconomic backgrounds of a revolution’s participants
21. Which of the following can be inferred about the “detailed judicial dossiers” referred to in line 49?
(A) Information contained in the dossiers sheds light on the social origins of a revolution’s participants.
(B) The dossiers closely resemble the narratives written by the revolution’s leaders in their personal memoirs.
(C) The information that such dossiers contain is untrustworthy and unrepresentative of a revolution’s participants.
(D) Social historians prefer to avoid such dossiers whenever possible because they are excessively detailed.
(E) The February Revolution of 1848 produced more of these dossiers than did the June insurrection.
22. Which of the following is the most logical objection to the claim made in lines 38-39?
(A) The February Revolution of 1848 is much less significant than the July insurrection of 1830.
(B) The backgrounds and motivations of participants in the July insurrection of 1830 have been identified, however cursorily.
(C) Even less is known about the July insurrection of 1830 than about the February Revolution of 1848.
(D) Historical records made during the July insurrection of 1830 are less reliable than those made during the May insurrection of 1871.
(E) The importance of the July insurrection of 1830 has been magnified at the expense of the significance of the February Revolution of 1848.
23. With which of the following statements regarding revolution would the author most likely agree?
(A) Revolutionary mobilization requires a great deal of planning by people representing disaffected groups.
(B) The objectives of the February Revolution were more radical than those of the June insurrection.
(C) The process of revolutionary mobilization varies greatly from one revolution to the next.
(D) Revolutions vary greatly in the usefulness of the historical records that they produce.
(E) As knowledge of the February Revolution increases, chances are good that its importance will eventually eclipse that of the June insurrection.
13.小说Mary Barton(原题)
Mary Barton, particularly in its early chapters, is a moving response to the suffering of the industrial worker in the England of the 1840’s. What is most impressive about the book is the intense and painstaking effort made by the author, Elizabeth Gaskell, to convey the experience of everyday life in working-class homes. Her method is partly documentary in nature: the novel includes such features as a carefully annotated reproduction of dialect, the exact details of food prices in an account of a tea party, an itemized description of the furniture of the Bartons’ living room, and a transcription (again annotated) of the ballad “The Oldham Weaver.” The interest of this record is considerable, even though the method has a slightly distancing effect.
As a member of the middle class, Gaskell could hardly help approaching working-class life as an outside observer and a reporter, and the reader of the novel is always conscious of this fact. But there is genuine imaginative re-creation in her accounts of the walk in Green Heys Fields, of tea at the Bartons’ house, and of John Barton and his friend’s discovery of the starving family in the cellar in the chapter “Poverty and Death.” Indeed, for a similarly convincing re-creation of such families’ emotions and responses (which are more crucial than the material details on which the mere reporter is apt to concentrate), the English novel had to wait 60 years for the early writing of D. H. Lawrence. If Gaskell never quite conveys the sense of full participation that would completely authenticate this aspect of Mary Barton, she still brings to these scenes an intuitive recognition of feelings that has its own sufficient conviction.
The chapter “Old Alice’s History” brilliantly dramatizes the situation of that early generation of workers brought from the villages and the countryside to the urban industrial centers. The account of Job Legh, the weaver and naturalist who is devoted to the study of biology, vividly embodies one kind of response to an urban industrial environment: an affinity for living things that hardens, by its very contrast with its environment, into a kind of crankiness. The early chapters—about factory workers walking out in spring into Green Heys Fields; about Alice Wilson, remembering in her cellar the twig-gathering for brooms in the native village that she will never again see; about Job Legh, intent on his impaled insects—capture the characteristic responses of a generation to the new and crushing experience of industrialism. The other early chapters eloquently portray the development of the instinctive cooperation with each other that was already becoming an important tradition among workers.
17. Which of the following best describes the author’s attitude toward Gaskell’s use of the method of documentary record in Mary Barton?
(A) Uncritical enthusiasm
(B) Unresolved ambivalence
(C) Qualified approval
(D) Resigned acceptance
(E) Mild irritation
18. According to the passage, Mary Barton and the early novels of D. H. Lawrence share which of the following?
(A) Depiction of the feelings of working-class families
(B) Documentary objectivity about working-class circumstances
(C) Richly detailed description of working-class adjustment to urban life
(D) Imaginatively structured plots about working-class characters
(E) Experimental prose style based on working-class dialect
19. Which of the following is most closely analogous to Job Legh in Mary Barton, as that character is described in the passage?
(A) An entomologist who collected butterflies as a child
(B) A small-town attorney whose hobby is nature photography
(C) A young man who leaves his family’s dairy farm to start his own business
(D) A city dweller who raises exotic plants on the roof of his apartment building
(E) A union organizer who works in a textile mill under dangerous conditions
20. It can be inferred from examples given in the last paragraph of the passage that which of the following was part of “the new and crushing experience of industrialism” (lines 46-47) for many members of the English working class in the nineteenth century?
(A) Extortionate food prices
(B) Geographical displacement
(C) Hazardous working conditions
(D) Alienation from fellow workers
(E) Dissolution of family ties
21. It can be inferred that the author of the passage believes that Mary Barton might have been an even better novel if Gaskell had
(A) concentrated on the emotions of a single character
(B) made no attempt to re-create experiences of which she had no firsthand knowledge
(C) made no attempt to reproduce working-class dialects
(D) grown up in an industrial city
(E) managed to transcend her position as an outsider
22. Which of the following phrases could best be substituted for the phrase “this aspect of Mary Barton” in line 29 without changing the meaning of the passage as a whole?
(A) the material details in an urban working-class environment
(B) the influence of Mary Barton on lawrence’s early work
(C) the place of Mary Barton in the development of the English novel
(D) the extent of the poverty and physical suffering among England’s industrial workers in the 1840’s
(E) the portrayal of the particular feelings and responses of working-class characters
23. The author of the passage describes Mary Barton as each of the following EXCEPT:
(A) insightful
(B) meticulous
(C) vivid
(D) poignant
(E) lyrical
14. 冰川和沉积物(据说是4月)
Tills are commonly classified according to the perceived process of deposition. However, it is increasingly recognised that this classification, which is mainly based on macroscopic field data, has severe limitations. At the same time the concept of the deforming glacier bed has become more realistic as a framework for discussing tills and their properties, and this (tectonic) concept is irreconcilable with the existing (depositional) till classification scheme. Over the last 20 years large thin sections have been used to
study tills, which has provided new insights into the textural and structural properties of tills. These results have revolutionised till sedimentology as they show that, in the main, subglacial tills possess deformational characteristics. Depositional properties are rare.
Based on this new insight the process of subglacial till formation is discussed in terms of glacier/ice sheet basal velocity, clay, water and carbonate content and the variability of these properties in space and time. The end result of this discussion is: till, the deforming glacier bed. To distinguish subglacial till from depositional sediments the term ‘tectomict’ is proposed. Within the single framework of subglacial till as the deforming glacier bed, many textural, structural and geomorphological features of till beds can be more clearly and coherently explained and understood.
旧：Till(冰碛)根据diposition(沉降)分类
新：根据deform(变形)分类
新旧冲突
最新发现：deform多，diposition少。
在deform的分类下讨论till可以解释很多问题
15. 云和气候变化预测
云对climate的影响。说科学家探究云对二氧化碳和温室效应有没有影响，结论是影响不大。第一云干嘛来着忘了，第二一种云在海上circulate什么什么。。然后最后一小节说科学家在电 脑上模拟的时候如果算云的话好象是说只能推测几天的天气，如果不算云的话就没这个问题，最后说还不如忽略云的影响。
As of the late 1980’s, neither theorists nor large-scale computer climate models could accurately predict whether cloud systems would help or hurt a warming globe. Some studies suggested that a four percent increase in stratocumulus clouds over the ocean could compensate for a doubling in atmospheric carbon dioxide, preventing a potentially disastrous planetwide temperature increase. On the other hand, an increase in cirrus clouds could increase global warming.
That clouds represented the weakest element in climate models was illustrated by a study of fourteen such models. Comparing climate forecasts for a world with double the current amount of carbon dioxide, researchers found that the models agreed quite well if clouds were not included. But when clouds were incorporated, a wide range of forecasts was produced. With such discrepancies plaguing the models, scientists could not easily predict how quickly the world’s climate would change, nor could they tell which regions would face dustier droughts or deadlier monsoons.
24. The author of the passage is primarily concerned with
(A) confirming a theory
(B) supporting a statement
(C) presenting new information
(D) predicting future discoveries
(E) reconciling discrepant findings
25. It can be inferred that one reason the fourteen models described in the passage failed to agree was that
(A) they failed to incorporate the most up-to-date information about the effect of clouds on climate
(B) they were based on faulty information about factors other than clouds that affect climate
(C) they were based on different assumptions about the overall effects of clouds on climate
(D) their originators disagreed about the kinds of forecasts the models should provide
(E) their originators disagreed about the factors other than clouds that should be included in the models
26. It can be inferred that the primary purpose of the models included in the study discussed in the second paragraph of the passage was to考缺陷，最后一句话改写
(A) predict future changes in the world’s climate
(B) predict the effects of cloud systems on the world’s climate
(C) find a way to prevent a disastrous planetwide temperature increase
(D) assess the percentage of the Earth’s surface covered by cloud systems
(E) estimate by how much the amount of carbon dioxide in the Earth’s atmosphere will increase
27. The information in the passage suggests that scientists would have to answer which of the following questions in order to predict the effect of clouds on the warming of the globe? 原文取非，D不对，光知道这个不行，因为还有别的云
(A) What kinds of cloud systems will form over the Earth?
(B) How can cloud systems be encouraged to form over the ocean?
(C) What are the causes of the projected planetwide temperature increase?
(D) What proportion of cloud systems are currently composed of cirrus of clouds?
(E) What proportion of the clouds in the atmosphere form over land masses?
作为20世纪80年代末，既不是理论家，也不是大规模的计算机气候模型能准确地预测云系是否会帮助或伤害变暖的地球。一些研究表明，增加百分之四以上的海洋层积云可以弥补大气中二氧化碳含量增加一倍，防止潜在的灾难性的planetwide温度升高。另一方面，卷云增加可能会加剧全球变暖。
，云代表由14个这样的模型的研究说明在气候模型中最薄弱的元素。双目前的二氧化碳量为世界气候的预测比较，研究人员发现，该模型很好同意如果不包括云层。但是，当云被纳入生产，广泛的预测。这种差异困扰模型，科学家们不能轻易预测全球气候改变的速度有多快，也无法告诉哪些地区将面临干旱dustier或致命的季风。
16. supernova (36套)
astronomers observe a supernova that is dimmer than expected because of dust screening，这个应该是36套里有，有点印象
If a supernova (the explosion of a massive star) triggered star formation from dense clouds of gas and dust, and if the most massive star to be formed from the cloud evolved into a supernova and triggered a new round of star formation, and so on, then a chain of star-forming regions would result. If many such chains were created in a differentially rotating galaxy, the distribution of stars would resemble the observed distribute in a spiral galaxy.
This line of reasoning underlies an exciting new theory of spiral-galaxy structure. A computer simulation based on this theory has reproduced the appearance of many spiral galaxies without assuming an underlying density wave, the hallmark of the most widely accepted theory of the large-scale structure of spiral galaxies. That theory maintains that a density wave of spiral form sweeps through the central plane of a galaxy, compressing clouds of gas and dust, which collapse into stars that form a spiral pattern. (160 words)
7. The primary purpose of the passage is to
(A) describe what results when a supernova triggers the creation of chains of star-forming regions
(B) propose a modification in the most widely accepted theory of spiral-galaxy structure
(C) compare and contrast the roles of clouds of gas and dust in two theories of spiral-galaxy structure
(D) describe a new theory of spiral-galaxy structure and contrast it with the most widely accepted theory
(E) describe a new theory of spiral-galaxy structure and discuss a reason why it is inferior to the most widely accepted theory
8. The passage implies that, according to the new theory of spiral-galaxy structure, a spiral galaxy can be created by supernovas when the supernovas are
(A) producing an underlying density wave
(B) affected by a density wave of spiral form
(C) distributed in a spiral pattern
(D) located in the central plane of a galaxy
(E) located in a differentially rotating galaxy
9. Which of the following, if true, would most discredit the new theory as described in the passage?
(A)The exact mechanism by which a star becomes a supernova is not yet completely known and may even differ for different stars.
(B) Chains of star-forming regions like those postulated in the new theory have been observed in the vicinity of dense clouds of gas and dust.
(C) The most massive stars formed from supernova explosions are unlikely to evolve into supernovas.
(D) Computer simulations of supernovas provide a poor picture of what occurs just before a supernova explosion.
(E) A density wave cannot compress clouds of gas and dust to a density high enough to create a star.
7. D 8.E 9.C
17.鸟叫研究(是原文吗??)
鸟的叫声的property,有两种类型，一种intergroup,另一种withgroup(不确定是不是这个叫 法)，intergroup很好的documented了，因为分布范围广，有差异什么的，鸟对特定叫声就作出特定反应，而withgroup研究困难， 因为鸟很少对鸣叫作出特定反应;问题中问到了recent research对intergroup研究到什么成果;
Over the years, biologists have suggested two main pathways by which sexual selection may have shaped the evolution of male birdsong. In the first, male competition and intrasexual selection produce relatively short, simple songs used mainly in territorial behavior. In the second, female choice and intersexual selection produce longer, more complicated songs used mainly in mate attraction; like such visual ornamentation as the peacock’s tail, elaborate vocal characteristics increase the male’s chances of being chosen as a mate, and he thus enjoys more reproductive success than his less ostentatious rivals. The two pathways are not mutually exclusive, and we can expect to find examples that reflect their interaction. Teasing them apart has been an important challenge to evolutionary biologists.
Early research confirmed the role of intrasexual selection. In a variety of experiments in the field, males responded aggressively to recorded songs by exhibiting territorial behavior near the speakers. The breakthrough for research into intersexual selection came in the development of a new technique for investigating female response in the laboratory. When female cowbirds raised in isolation in sound-proof chambers were exposed to recordings of male song, they responded by exhibiting mating behavior. By quantifying the responses, researchers were able to determine what particular features of the song were most important. In further experiments on song sparrows, researchers found that when exposed to a single song type repeated several times or to a repertoire of different song types, females responded more to the latter. The beauty of the experimental design is that it effectively rules out confounding variables; acoustic isolation assures that the female can respond only to the song structure itself.
If intersexual selection operates as theorized, males with more complicated songs should not only attract females more readily but should also enjoy greater reproductive success. At first, however, researchers doing fieldwork with song sparrows found no correlation between larger repertoires and early mating, which has been shown to be one indicator of reproductive success; further, common measures of male quality used to predict reproductive success, such as weight, size, age, and territory, also failed to correlate with song complexity.
The confirmation researchers had been seeking was finally achieved in studies involving two varieties of warblers. Unlike the song sparrow, which repeats one of its several song types in bouts before switching to another, the warbler continuously composes much longer and more variable songs without repetition. For the first time, researchers found a significant correlation between repertoire size and early mating, and they discovered further that repertoire size had a more significant effect than any other measure of male quality on the number of young produced. The evidence suggests that warblers use their extremely elaborate songs primarily to attract females, clearly confirming the effect of intersexual selection on the evolution of birdsong.
21. The passage is primarily concerned with
(A) showing that intrasexual selection has a greater effect on birdsong than does intersexual selection
(B) contrasting the role of song complexity in several species of birds
(C) describing research confirming the suspected relationship between intersexual selection and the complexity of birdsong
(D) demonstrating the superiority of laboratory work over field studies in evolutionary biology
(E) illustrating the effectiveness of a particular approach to experimental design in evolutionary biology
22. The author mentions the peacock’s tail in line 8 most probably in order to
(A) cite an exception to the theory of the relationship between intrasexual selection and male competition
(B) illustrate the importance of both of the pathways that shaped the evolution of birdsong
(C) draw a distinction between competing theories of intersexual selection
(D) give an example of a feature that may have evolved through intersexual selection by female choice
(E) refute a commonly held assumption about the role of song in mate attraction
23. According to the passage, which of the following is specifically related to intrasexual selection?
(A) Female choice
(B) Territorial behavior
(C) Complex song types
(D) Large song repertoires
(E) Visual ornamentation
24. Which of the following, if true, would most clearly demonstrate the interaction mentioned in lines 11-13?
(A) Female larks respond similarly both to short, simple songs and to longer, more complicated songs.
(B) Male canaries use visual ornamentation as well as elaborate song repertoires for mate attraction.
(C) Both male and female blackbirds develop elaborate visual and vocal characteristics.
(D) Male jays use songs to compete among themselves and to attract females.
(E) Male robins with elaborate visual ornamentation have as much reproductive success as rivals with elaborate vocal characteristics.
25. The passage indicates that researchers raised female cowbirds in acoustic isolation in order to
(A) eliminate confounding variables
(B) approximate field conditions
(C) measure reproductive success
(D) quantify repertoire complexity
(E) prevent early mating
26. According to the passage, the song sparrow is unlike the warbler in that the song sparrow
(A) uses songs mainly in territorial behavior
(B) continuously composes long and complex songs
(C) has a much larger song repertoire
(D) repeats one song type before switching to another
(E) responds aggressively to recorded songs
27. The passage suggests that the song sparrow experiments mentioned in lines 37-43 failed to confirm the role of intersexual selection because
(A) females were allowed to respond only to the song structure
(B) song sparrows are unlike other species of birds
(C) the experiments provided no evidence that elaborate songs increased male reproductive success
(D) the experiments included the songs of only a small number of different song sparrows
(E) the experiments duplicated some of the limitations of previous field studies
18.恐龙灭绝和行星撞地球
说65万年前恐龙灭绝是因为comet or other meterite的impact 造成的，其证据是因为在一个考古地方，65万年前的， 发现了一种元素Ir, 记不清具体的了，因为这种元素在地球很少见，只能是由于行星的撞击，因为非地球的行星富含这种元素，然后由于撞击而留在地球上，故可由此元素的含量来推测是行星撞击的。 同时在距今大概120万年的地方也发现了该元素，但是其含量只有65万年的十分之一，同时文章开头的意思是要证明120万年的这个也是由于行星撞击造成的。 文章最后结尾说起撞击的行星也有可能含这种元素较少，而且comet全是由冰构成的， 所以撞击120的那个可能只是一个小星星， 只能引起小范围的灭绝，不能引起全部的生物灭绝，但是65的那种是全球灭绝。
题目有一道问你， 由于120 的Ir元素只有65的十分之一，则可以推测120的那颗星星与65导致恐龙灭绝的那颗有什么区别， 我选的是那个Ir元素含量与行星撞击的impact没有直接联系 。
Iridium, a hard, whitish metal similar to platinum, is extremely rare on Earth. Extremely high concentrations of iridium on Earth result from only two scenarios: massive volcanic eruptions that release iridium from deep within the Earth and meteorites that shower down on Earth from space. When scientists found concentrations of iridium 30 times higher than normal in rock stratum from 65 million years ago, they concluded that a massive meteor or comet hit the Earth and caused the massive extinction of the dinosaurs.
Which of the following, if true, most strongly supports the scientist’s conclusion?
A. Volcanoes massive enough to generate high concentrations of iridium are very rare.
B. Massive volcanic eruptions occurred frequently 80 million years ago.
C. Most scientists support the hypothesis that a cosmic impact wiped out the dinosaurs.
D. The massive extinction that occurred 70 million years ago killed not only the dinosaurs but also 70 percent of all life on Earth.
E. A comet struck the earth some 120 million years ago, but no widespread extinction occurred.
