[外语类试卷]大学英语四级改革适用(阅读)模拟试卷130及答案与解析.doc
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1、大学英语四级改革适用(阅读)模拟试卷 130及答案与解析 Section A 0 When medal-winning athletes return home from the Olympic Games, their fame may be short-lived, but they can look forward to a long life. A new study has found that Olympic medalists live an average of 2.8 years longer than the【 C1】 _of us, whether theyre a gy
2、mnast, golfer, runner, or athlete in any other event. The study used data on 15 174 male and female athletes who won medals in Olympic Games since 1896 and found that 30 years after any【 C2】 _Olympics, 8% more medalists were alive than others from their country and birth year. The effect, a second s
3、tudy concluded, wasnt【 C3】 _seen in Olympic athletes who【 C4】 _in high-endurance or high-intensity events. Researchers found no difference in mortality between cyclists, rowers, tennis stars, and cricket【 C5】 _. But the factor that did make a difference: whether a sport had high levels of physical【
4、C6】 _and collisions. Olympians in sports with higher bodily collision, such as boxing, had an 11% higher mortality【 C7】 _than those in sports with minimal collisions. Both studies were published online today in British Medical Journal. The researchers【 C8】 _that medalists could live longer because o
5、f their intensive training, exercise levels throughout life, or because their success leads to【 C9】 _wealth or education levels, but more research will be needed to【 C10】_what is at play. A)assume F)hardly K)participated B)attracted G)healthy L)players C)contact H)increased M)quality D)determine I)i
6、nfluence N)rest E)given J)just O)risk 1 【 C1】 2 【 C2】 3 【 C3】 4 【 C4】 5 【 C5】 6 【 C6】 7 【 C7】 8 【 C8】 9 【 C9】 10 【 C10】 Section B 10 Ecosystems in and out of Balance A)It is known that ecosystems have a structure consisting of producers(green plants which use light energy to produce living matter fr
7、om non-living matter in the environment), consumers(all the animals which feed directly or indirectly on the green plants), and decomposers(分解体 )(bacteria and fungi that change the dead organic material back into simple raw materials which can then again be used by the producers). This structure, wh
8、ich is necessary to maintain the flow of energy and nutrients through the system, consists of the interactions between hundreds or even thousands of different kinds of plants, animals, and microbes which grow, reproduce and die in a never-ending cycle. B)At this point, we might ask ourselves, since
9、ecosystems consist of interactions between reproduction populations, what prevents one species(kind)of organism from reproducing in such numbers that it overcomes and eliminates other species? In other words, what are the factors that maintain the structure, or balance, of that ecosystem? To answer
10、the question we must first recognize that the idea of ecosystem balance is relative. In fact, ecosystems are always changing and adjusting. The relative degree of balance is the main factor in determining the rate of change. A well-balanced system will change very slowly, perhaps unnoticeably, in th
11、e course of direct human experience. An unbalanced system changes more or less rapidly; the greater the imbalance, the more rapid the change. It follows that if a change is made in one or more of the factors that affect balance, the ecosystem itself will also change. C)One way of viewing ecosystem c
12、hange and balance is in terms of the two factors: biotic potential and environmental resistance. The biotic potential of a species is its capacity for reproducing itself; in a general sense it is the combination of all the factors that permit its kind to become more numerous. Birth rate is an obviou
13、s factor, but it is only one. Given favorable conditions, every species has a biotic potential to increase its population. For example, a pair of frogs has the biotic potential to produce several hundred offspring in one season and each offspring in turn could potentially produce several hundred mor
14、e. D)The fact that populations in nature generally do not “explode“ in numbers is not due to limits in biotic potential, but to a second factor, environmental resistance. The environmental resistance facing each species is the combination of all the factors that limit the survival of its members. Th
15、ese factors are similar for both plants and animals. Thus, there is a relationship between biotic potential and environmental resistance. If the environmental resistance for a species is less than its biotic potential, its members will increase; if the environmental resistance is greater than biotic
16、 potential, then its numbers will decrease. In a stable ecosystem, the biotic potential of each species is evenly balanced by environmental resistance. E)Now lets look at ourselves as a species in relation to ecosystem balance. Modern scientists believe that humankind, like other animals, evolved th
17、rough millions of years of changes and adaptations to the environment. Despite this similarity with other creatures, however, the evolution of humankind differs from that of other species in one important and unique way. In other species evolution has led to specialization, both in the species abili
18、ties and in its place within the environmental structure. For example, the giraffe(长颈鹿 )is marvelously adapted to grazing on treetops but, as such, it is also specialized and thus restricted to grazing on trees and shrubs(灌木 ). The same is true for countless other species. For humankind the reverse
19、is true. Our evolution had led to a very generalized capability. Our highly developed intelligence and ability to make and handle tools mean that we can do virtually anything. Rather than evolving into a specialized role in balance with natural enemies, competitive species and environmental factors,
20、 humans evolved in such a way that we are capable of moving into every environment on Earth and even into space. Said another way, we see in humankind a tremendous imbalance between biotic potential and environmental resistance. The result is the rapidly increasing world population, frequently refer
21、red to as the population explosion. Further, to support our growing population, natural ecosystems are being increasingly displaced by human habitations, agriculture, and other human-supporting activities. F)From the viewpoint of evolutionary history, the spreading of human beings over the earth can
22、 be looked at as a natural process, the latest of many waves of change that have occurred since the earliest beginnings of life on this planet. Unfortunately, there is nothing in ecological or evolutionary theory to support the view that humans will be the last or even a long-lasting “wave“. In fact
23、, there are many indications that the human wave, at least that of humans in a technological society, may be relatively short lived. Why is it so? First the rate and degree of many changes being brought about by humans are extreme. Previous evolutionary changes have occurred over the course of many
24、millions of years. Thus the slow process of readaptation and development of new species more or less balanced extinctions, and ecosystems remained in relative balance throughout the course of change. In contrast, the significant changes brought about by humans have occurred in only the last 200 year
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