1、大学英语六级改革适用（阅读）模拟试卷 73及答案与解析 Section B 0 How Much Higher? How Much Faster? A)Since the early years of the twentieth century, when the International Athletic Federation began keeping records, there has been a steady improvement in how fast athletes run, how high they jump and how far they are able to
2、hurl massive objects, themselves included, through space. B)For the so-called power events that require a relatively brief, explosive release of energy, like the 100-metre sprint and the long jump-times and distances have improved ten to twenty percent. In the endurance events the results have been
3、more dramatic. At the 1908 Olympics, John Hayes of the U.S. team ran to marathon in a time of 2:55:18. In 1999, Moroccos Khalid Khannouchi set a new world record of 2:05:42, almost thirty percent faster. C)No one theory can explain improvements in performance, but the most important factor has been
4、genetics. “The athlete must choose his parents carefully,“ says Jesus Dapena, a sports scientist at Indiana University, invoking an oft-cited adage. D)Over the past century, the composition of the human gene pool has not changed appreciably, but with increasing global participation in athletics-and
5、greater rewards to tempt athletes-it is more likely that individuals possessing the unique complement of genes for athletic performance can be identified early. “Was there someone likesprinterMichael Johnson in the 1920s?“ Dapena asks. “Im sure there was, but his talent was probably never realized.“
6、 E)Identifying genetically talented individuals is only the first step. Michael Yessis, an emeritus professor of Sports Science at California State University at Fullerton, maintains that “genetics only determines about one third of what an athlete can do. But with the right training we can go much
7、further with that one third than weve been going.“ Yessis believes that U.S. runners, despite their impressive achievements, are “running on their genetics“. F)By applying more scientific methods, “theyre going to go much faster“. These methods include strength training that duplicates what they are
8、 doing in their running events as well as plyometrics, a technique pioneered in the former Soviet Union. G)Whereas most exercises are designed to build up strength or endurance, plyometrics focuses on increasing power the rate at which an athlete can expend energy. When a sprinter runs, Yesis explai
9、ns, her foot stays in contact with the ground for just under a tenth of a second, half of which is devoted to landing and the other half to pushing off. Plyometric exercises help athletes make the best use of this brief interval. H)Nutrition is another area that sports trainers have failed to addres
10、s adequately. “Many athletes are not getting the best nutrition, even through supplements,“ Yessis insists. Each activity has its own nutritional needs. Few coaches, for instance, understand how deficiencies in trace minerals can lead to injuries. I)Focused training will also play a role in enabling
11、 records to be broken. “If we applied the Russian training model to some of the outstanding runners we have in this country,“ Yessis asserts, “they would be breaking records left and right.“ He will not predict by how much, however: “Exactly what the limits are its hard to say, but there will be inc
12、reases even if only by hundredths of a second, as long as our training continues to improve.“ J)One of the most important new methodologies is biomechanics, the study of the body in motion. A biomechanic films an athlete in action and then digitizes her performance, recording the motion of every joi
13、nt and limb in three dimensions. By applying Newton s law to these motions, “we can say that this athlete s run is not fast enough; that this one is not using his arms strongly enough during take-off,“ says Dapena, who uses these methods to help high jumpers. To date, however, biomechanics has made
14、only a small difference to athletic performance. K)Revolutionary ideas still come from the athletes themselves. For example, during the 1968 Olympics in Mexico City, a relatively unknown high jumper named Dick Fosbury won the gold by going over the bar backwards, in complete contradiction of all the
15、 received high-jumping wisdom, a move instantly dubbed the Fosbury flop. Fosbury himself did not know what he was doing. That understanding took the later analysis of biomechanics specialists who put their minds to comprehending something that was too complex and unorthodox ever to have been invente
16、d through their own mathematical simulations. L)Fosbury also required another element that lies behind many improvements in athletic performance: an innovation in athletic equipment. In Fosburys case, it was the cushions that jumpers land on. Traditionally, high jumpers would land in pits filled wit
17、h sawdust. But by Fosburys time, sawdust pits had been replaced by soft foam cushions, ideal for flopping. M)In the end, most people who examine human performance are humbled by the resourcefulness of athletes and the powers of the human body. “Once you study athletics, you learn that its a vexingly
18、 complex issue,“ says John S. Raglin, a sports psychologist at Indiana University. “Core performance is not a simple or mundane thing of higher, faster, longer. So many variables enter into the equation, and our understanding in many cases is fundamental. Were got a long way to go.“ For the foreseea
19、ble future, records will be made to be broken. 1 Another factor found by Fosbury is that equipment also contributes to athletic performance. 2 The fact that athletes are easily got hurt due to lacking of trace minerals has not been recognized by most trainers. 3 Modern official athletic records date
20、 from about 1900. 4 Only by inheriting good genes and adopting scientific training can athletes achieve excellent performance. 5 According to Jesus Dapena, genetics should be given to the priority among all elements. 6 One latest method to analyze body movement in action is biomechanics, which has s
21、lightly influence on athletic performance by now. 7 Scientists believe our current knowledge of athletics is basic. 8 Athlete himself created new ways like Fosbury flop, which directly made Fosbury win a gold metal. 9 Performance has improved most greatly in events requiring endurance. 10 The growin
22、g international importance of athletics led talented athletes to be recognized at a younger age. 10 Think or Swim:Can We Hold Back the Oceans? A)As the world gets warmer, sea levels are rising. It has been happening at a snail s pace so far, but as it speeds up more and more low-lying coastal land w
23、ill be lost. At risk are many of the worlds cities and huge areas of fertile farmland. The sea is set to rise a meter or more by the end of this century. And that s just the start. “Unless there is a rapid and dramatic about-face in emissions which no one expects the next century will be far worse t
24、han this century,“ says glaciologist(冰川学家 )Bob Bindshadler of NASA s Goddard Space Flight Center, Maryland. B)Throwing trillions of dollars at the problem could probably save big cities such as New York and London, but the task of defending all low-lying coastal areas and islands seems hopeless. Or
25、is it? Could we find a way to slow the accelerating glaciers, drain seas into deserts or add more ice to the great ice caps of Greenland and Antarctica? C)These ideas might sound crazy but we have got ourselves into such a bad situation that maybe we should start to consider them. If we carry on as
26、we are, sea levels will rise for millennia, probably by well over 10 meters. Slashing greenhouse gas emissions would slow the rise, but the longer we hesitate, the bigger the rise we will be committed to. Even if “conventional“ geo-engineering schemes for cooling the planet were put in place and wor
27、ked as planned, they would have little effect on sea level over the next century unless combined with drastic emissions cuts. D)In short, if coastal dwellers dont want their children and grandchildren to have abandon land to the sea, now is the time to start coming up with Plan C. So New Scientist s
28、et out in search of the handful of researchers who have begun to think about specific ways to hold back the waters. E)One of the reasons why the great ice sheets of Greenland and Antarctic are already shrinking is that the ice is draining off the land faster. Ice floating on the surrounding seas usu
29、ally acts as a brake, holding back glaciers on land, so as this ice is lost the glaciers flow faster. The acceleration of the Jakobshavn glacier in Greenland is thought to be the result of warm currents melting the floating tongue of the glacier. Other outlet glaciers are being attacked in a similar
30、 way. F)Mike MacCracken of the Climate Institute in Washington DC is one of those starting to think that we shouldnt just sit back and let warm currents melt ice shelves. “Is there some way of doing something to stop that flow, or cool the water?“ he asks. G)Last year, physicist Russel Seitz at Harv
31、ard University suggested that the planet could be cooled by using fleets of customized boats to generate large numbers of tiny bubbles. This would whiten the surface of the oceans and so reflect more sunlight. MacCracken says the bubbles might be better arranged in a more focused way, to cool the cu
32、rrents that are undermining the Jakobshavn glacier and others like it. A couple of degrees of chill would take this water down to freezing point, rendering it harmless. “At least that would slow the pace of change,“ MacCracken says. H)What about a more direct approach: building a physical barrier to
33、 halt a glaciers flow into the sea by brute force? Bindshadler thinks that is a non-starter. “The ice discharge has many sources, mostly remote and in environments where barriers are not likely to work,“ he says. “Taking just the one example I know best, the Pine Island glacier in Antarctic drains i
34、nto an ice shelf that at its front is 25 kilometers across and 500 meters thick, and moves at over 10 meters per day. The seabed there is 1000 meters down and is made of sediment(沉淀物 )hundreds of metres thick and the consistency of toothpaste.“ Not your ideal building site. I)A slightly more subtle
35、scheme to rein in the glaciers was proposed more than 20 years ago by Douglas MacAyeal of the University of Chicago. His idea is to fight ice with ice. The big outlet glaciers feed into giant floating shelves of ice, which break off into icebergs at their outer edges. MacAyeal suggested pumping wate
36、r up from beneath the ice and depositing it on the upper surface, where it would freeze to form a thick ridge, weighing down the floating ice shelf. Add enough ice in this way, and the bottom of the ice shelf would eventually be forced down onto the seabed. Friction with the seabed would slow down t
37、he shelfs movement, which in turn would hold back the glaciers feeding into it. It would be like tightening an immense valve. J)“I think its quite an inspired idea,“ says Bindshadler. But nobody has followed it up to work out how practical the scheme would be. “On the back of an envelope it has prom
38、ise but these ice shelves are big. You would need a lot of drilling equipment all over the ice shelf, and my intuition is that if you look at the energetic of it, it won t work,“ Bindshadler says. K)Even if we could apply brakes to glaciers, this would only slow down sea level rise. Could we do bett
39、er than that and reverse it actually make the sea retreat? If you think of the sea as a giant bathtub, then the most obvious way to lower its level is to take out the plug. L)“One of the oldest notions is filling depressions on the land,“ says MacCracken. Among the largest of these is the Qattara de
40、pression in northern Egypt, which at its lowest point is more than 130 meters below sea level. Various schemes have been proposed to channel water from the Mediterranean into the depression to generate hydroelectric(水力的 )power, and as a by-product a few thousand cubic kilometers of the sea would be
41、drained away. Unfortunately, thats only enough to shave about 3 millimeters off sea level: a drop in the ocean. And there would be grave consequences for the local environment. “The leakage of salt water through fracture systems would add salt to aquifers(含水层 )for good,“ says Farouk El-Baz, a geolog
42、ist at Boston University who has studied the region. M)Refilling the Dead Sea is no better. Because of surrounding hills, this depression could be filled to 60 meters above sea level, but even that would only offset the rise by 5 millimeters and drown several towns into the bargain. N)The notion of
43、engineering lower sea levels remains a highly abstract topic. “If the world doesnt control emissions, Im pretty sure that no geo-engineering solution will work and it would potentially create other side effects and false promises,“ says MacCcracken. “But if we do get on a path to curbing emissions h
44、ump we re going to go through over the next few centuries?“ 11 The ice floating on the surrounding seas can stop the glaciers move away. 12 Filling depressions can only offset very little rise of sea levels. 13 A physicists suggestion to cool the planet is to generating tiny bubbles with fleets of c
45、ustomised boats. 14 Sea levels are rising very slowly at present. 15 Someone advised to pump water up from beneath the ice to weigh down the floating ice shelf. 16 One of the oldest ways to retreat the sea is to fill depressions on the land. 17 Building physical barriers to keep glaciers may not be
46、practical. 18 Spending trillions of dollars at sea-level rise problem could probably save only a few cities. 19 People once believed that channeling water from the sea into some depression could both generate electricity and drain away some sea water. 20 The idea of pumping water up from beneath the
47、 ice may not work because it consumes too much energy. 20 The Truth about the Environment A)For many environmentalists, the world seems to be getting worse. They have developed a hit-list our main fears: that natural resources are running out; that the population is ever growing, leaving less and le
48、ss to eat; that species are becoming extinct in vast numbers, and that the planet s air and water are becoming ever more polluted. B)But a quick look at the facts shows a different picture. First, energy and other natural resources have become more abundant, not less so, since the book The Limits to
49、 Growth was published in 1972 by a group of scientists. Second, more food is now produced per head of the world s population than at any time in history. Fewer people are starving. C)Third, although species are indeed becoming extinct, only about 0.7% of them are expected to disappear in the next 50 years, not 25-50%, as has so often been predicted. And finally, most forms of environmental pollution either appear to have been exaggerated, or are transient-associated with the early phase of industrialisation and therefore be
