1、大学英语六级改革适用（阅读）模拟试卷 208及答案与解析 Section C 0 A massive pool of warm ocean water is causing changes in the atmosphere that could produce unusual weather around the world in the next few months, the US National Weather Service reported on Monday. As a result of this phenomenon, known as El Nino, more rain
2、fall than normal is likely this winter across some areas of the United States, with unusually warm or cold weather in other parts of the country. Currently the phenomenon is marked by a warm pool of water along the equator extending from the International Date Line nearly to the coast of South Ameri
3、ca. That water is nearly 4 degrees Fahrenheit above normal, explained Vernon Kousky of the climate center. This warm water “spreads almost a quarter of the way around the globe. So its massive and it has an impact on our weather. It has a “global influence. because it disturbs the atmosphere“, said
4、Dave Rodenhuis, director of the climate center. “El Nino is probably the most important climate event beyond the annual cycle of seasons“, he added. Because the changes tended to be first noticed around Christmas, the phenomenon was given the name El Nino, which is Spanish for child, a term often us
5、ed to refer to the baby Jesus. The phenomenon occurs every three to five years, sometimes in a mild form and sometimes strongly affecting weather patterns worldwide. Details of its cause are not fully understood, but when it occurs, unusually warm air can be pumped into Canada, Alaska and the northe
6、rn United States. At the same time, conditions tend to be wetter than normal along the US Southeast Coast and the Gulf of Mexico. And the Atlantic and Caribbean hurricane season tends to be milder than usual. The strong El Nino of 1982-1983 was blamed for worsening the devastating drought in Africa,
7、 causing a series of severe winter storms to come ashore in California, spawning the first typhoon to strike French Polynesia in 75 years followed by five more in five months deluging Peru and Ecuador with torrential rains and promoting the worst drought in two centuries in Australia Overall damage
8、was estimated at between $2 billion and $8 billion by a United Nations analysis and the death toll topped 1,500 worldwide. 1 El Nino can best be described as _. （ A） unusually long period of hot or cold weather （ B） unusual changes of weather around the world （ C） atmospheric change caused by warm o
9、cean water （ D） rising temperature of the ocean water and atmosphere 2 The warm water is affecting the weather globally because _. （ A） its temperature is too much above normal （ B） it covers a vast area in the world （ C） it is one of the most important climate events （ D） its influence begins from
10、the equator 3 Which of the following is true about the naming of El Nino? （ A） The name had something to do with Christianity. （ B） The name was given by a religious researcher. （ C） The name indicates that El Nino most usually happens around Christmas. （ D） The name implies that the first phenomeno
11、n of El Nino appeared in Spain. 4 What is least known about El Nino, according to the passage? （ A） The climate changes caused by El Nino. （ B） The areas influenced by El Nino. （ C） How often El Nino happens. （ D） How El Nino is formed. 5 What does the author wants to tell us about El Nino by the la
12、st two paragraphs? （ A） The UNs concern about it. （ B） The measures taken against it. （ C） Its intensity. （ D） Its frequency. 5 When global warming finally came, it stuck with a vengeance(异乎寻常地 ). In some regions, temperatures rose several degrees in less than a century. Sea levels shot up nearly 40
13、0 feet, flooding coastal settlements and forcing people to migrate inland. Deserts spread throughout the world as vegetation shifted drastically in North America, Europe and Asia. After driving many of the animals around them to near extinction, people were forced to abandon their old way of life fo
14、r a radically new survival strategy that resulted in widespread starvation and disease. The adaptation was farming: the global-warming crisis that gave rise to it happened more than 10,000 years ago. As environmentalists convene in Rio de Janeiro this week to ponder the global climate of the future,
15、 earth scientists are in the midst of a revolution in understanding how climate has changed in the past and how those changes have transformed human existence. Researchers have begun to piece together an illuminating picture of the powerful geological and astronomical forces that have combined to ch
16、ange the planets environment from hot to cold, wet to dry and back again over a time period stretching back hundreds of millions of years. Most important, scientists are beginning to realize that the climatic changes have had a major impact on the evolution of the human species. New research now sug
17、gests that climate shifts have played a key role in nearly every significant turning point in human evolution: from the dawn of primates(灵长目动物 )some 65 million years ago to human ancestors rising up to walk on two legs, from the huge expansion of the human brain to the rise of agriculture. Indeed, t
18、he human history has not been merely touched by global climate change, some scientists argue, it has in some instances been driven by it. The new research has profound implications for the environmental summit in Rio. Among other things, the findings demonstrate that dramatic climate change is nothi
19、ng new for planet Earth. The benign(宜人的 )global environment that has existed over the past 10,000 years during which agriculture, writing, cities and most other features of civilization appeared is a mere bright spot in a much larger pattern of widely varying climate over the ages. In fact, the patt
20、ern of climate change in the past reveals that Earths climate will almost certainly go through dramatic changes in the future even without the influence of human activity. 6 Farming emerged as a survival strategy because man had been obliged_. （ A） to give up his former way of life （ B） to leave the
21、 coastal areas （ C） to follow the ever-shifting vegetation （ D） to abandon his original settlement 7 Earth scientists have come to understand that climate _. （ A） is going through a fundamental change （ B） has been getting warmer for 10,000 years （ C） will eventually change from hot to cold （ D） has
22、 gone through periodical changes 8 Scientists believe that human evolution _. （ A） has seldom been accompanied by climatic changes （ B） has exerted little influence on climatic changes （ C） has largely been affected by climatic changes （ D） has had a major impact on climatic changes 9 Evidence of pa
23、st climatic changes indicates that _. （ A） human activities have accelerated changes of Earths environment （ B） Earths environment will remain mild despite human interference （ C） Earths climate is bound to change significantly in the future （ D） Earths climate is unlikely to undergo substantial cha
24、nges in the future 10 The message the author wishes to convey in the passage is that_. （ A） human civilization remains glorious though it is affected by climatic changes （ B） mankind is virtually helpless in the face of the dramatic changes of climate （ C） man has to limit his activities to slow dow
25、n the global warming process （ D） human civilization will continue to develop in spite of the changes of nature 10 Most growing plants contain much more water than all other materials combined. C. R. Barnes has suggested that it is as proper to term the plant a water structure as to call a house com
26、posed mainly of brick a brick building. Certain it is that all essential processes of plant growth and development occur in water. The mineral elements from the soil that are usable by the plant must be dissolved in the soil solution before they can be taken into the root. They are carried to all pa
27、rts of the growing plant and are built into essential plant materials while in a dissolved state. The carbon dioxide(CO2)from the air may enter the leaf as a gas but is dissolved in water in the leaf before it is combined with a part of the water to form simple sugars the base material from which th
28、e plant body is mainly built. Actively growing plant parts are generally 75 to 90 percent water. Structural parts of plants, such as woody stems no longer actively growing, may have much less water than growing tissues. The actual amount of water in the plant at any one time, however, is only a very
29、 small part of what passes through it during its development. The processes of photosynthesis, by which carbon dioxide and water are combined in the presence of chlorophyll(叶绿素 )and with energy derived from light to form sugars, require that carbon dioxide from the air enter the plant. This occurs m
30、ainly in the leaves. The leaf surface is not solid but contains great numbers of minute openings, through which the carbon dioxide enters. The same structure that permits the one gas to enter the leaf, however, permits another gas water vapor to be lost from it. Since carbon dioxide is present in th
31、e air only in trace quantities(3 to 4 parts in 10,000 parts of air)and water vapor is near saturation in the air spaces within the leaf(at 80F, saturated air would contain about 186 parts of water vapor in 10,000 parts of air), the total amount of water vapor lost is many times the carbon dioxide in
32、take. Actually, because of wind and other factors, the loss of water in proportion to carbon dioxide intake may be even greater than the relative concentrations of the two gases. Also, not all of the carbon dioxide that enters the leaf is synthesized into carbohydrates(碳水化合物 ). 11 A growing plant ne
33、eds water for all of the following except _. （ A） forming sugars （ B） sustaining woody stems （ C） keeping green （ D） producing carbon dioxide 12 The essential function of photosynthesis in terms of plant needs is _. （ A） to form sugars （ B） to derive energy from light （ C） to preserve water （ D） to
34、combine carbon dioxide with water 13 The second paragraph uses facts to develop the essential idea that _. （ A） a plant efficiently utilizes most of the water it absorbs （ B） carbon dioxide is the essential substance needed for plant development （ C） a plant needs more water than is found in its com
35、position （ D） the stronger the wind, the more the water vapor loss 14 From the passage, we learn that _. （ A） the mineral elements will not be absorbed by the plant unless they are dissolved in its root （ B） the woody stems contain more water than the leaves （ C） air existing around the leaf is foun
36、d to be saturated （ D） only part of the carbon dioxide in the plants is synthesized 15 This passage is mainly about _. （ A） the functions of carbon dioxide and water （ B） the role of water in a growing plant （ C） the process of simple sugar formation （ D） the synthesis of water with carbon dioxide 1
37、5 Birds that are literally half-asleep with one brain hemisphere alert and the other sleeping control which side of the brain remains awake, according to a new study of sleeping ducks. Earlier studies have documented half-brain sleep in a wide range of birds. The brain hemispheres take turns sinking
38、 into the sleep stage characterized by slow brain waves. The eye controlled by the sleeping hemisphere keeps shut, while the wakeful hemispheres eye stays open and alert. Birds also can sleep with both hemispheres resting at once. Decades of studies of bird flocks led researchers to predict extra al
39、ertness in the more vulnerable, end-of-the-row sleepers. Sure enough, the end birds tended to watch carefully on the side away from their companions. Ducks in the inner spots showed no preference for gaze direction. Also, birds doping(打盹 )at the end of the line resorted to single-hemisphere sleep, r
40、ather than total relaxation, more often than inner ducks did. Rotating 16 birds through the positions in a four-duck row, the researchers found outer birds half-asleep during some 32 percent of dozing time versus about 12 percent for birds in internal spots. “We believe this is the first evidence fo
41、r an animal behaviorally controlling sleep and wakefulness simultaneously in different regions of the brain,“ the researchers say. The results provide the best evidence for a long-standing supposition that single-hemisphere sleep evolved as creatures scanned for enemies. The preference for opening a
42、n eye on the lookout side could be widespread, he predicts. Hes seen it in a pair of birds dozing side-by-side in the zoo and in a single pet bird sleeping by a mirror. The mirror-side eye closed as if the reflection were a companion and the other eye stayed open. Useful as half-sleeping might be, i
43、ts only been found in birds and such water mammals(哺乳动物 )as dolphins, whales, and seals. Perhaps keeping one side of the brain awake allows a sleeping animal to surface occasionally to avoid drowning. Studies of birds may offer unique insights into sleep. Jerome M. Siegel of the UCLA says he wonders
44、 if birds half-brain sleep “is just the tip of the iceberg(冰山 ).“ He speculates that more examples may turn up when we take a closer look at other species. 16 A new study on birds sleep has revealed that_. （ A） half-brain sleep is found in a wide variety of birds （ B） half-brain sleep is characteriz
45、ed by slow brain waves （ C） birds can control their half-brain sleep consciously （ D） birds seldom sleep with the whole of their brain at rest 17 According to the passage, birds often half sleep because _. （ A） they have to watch out for possible attacks （ B） their brain hemispheres take turns to re
46、st （ C） the two halves of their brain are differently structured （ D） they have to constantly keep an eye on their companions 18 The example of a bird sleeping in front of a mirror indicates that _. （ A） the phenomenon of birds dozing in pairs is widespread （ B） birds prefer to sleep in pairs for th
47、e sake of security （ C） even an imagined companion gives the bird a sense of security （ D） a single pet bird enjoys seeing its own reflection in the mirror 19 While sleeping, some water mammals tend to keep half awake in order to_. （ A） alert themselves to the approaching enemy （ B） emerge from wate
48、r now and then to breathe （ C） be sensitive to the ever-changing environment （ D） avoid being swept away by rapid currents 20 By “just the tip of the iceberg“(Line 2, Para. 8), Siegel suggests that_. （ A） half-brain sleep has something to do with icy weather （ B） the mystery of half-brain sleep is c
49、lose to being solved （ C） most birds living in cold regions tend to be half sleepers （ D） half-brain sleep is a phenomenon that could exist among other species 20 The destruction of our natural resources and contamination of our food supply continue to occur, largely because of the extreme difficulty in affixing(把 固定 )legal responsibility on those who continue to treat our environment with reckless abandon. Attempts to prevent pollution by legislation, economic incentives and friendly pers
