大学英语六级-158及答案解析.doc

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1、大学英语六级-158 及答案解析(总分：100.00，做题时间：90 分钟)一、Reading Comprehensio(总题数：5，分数：100.00)How Exercise Could Lead to a Better BrainA. The value of mental-training games may be speculative, as Dan Hurley writes in his article on the quest to make ourselves smarter, but there is another, easy-to-achieve, scientifi

2、cally proven way to make yourself smarter. Go for a walk or a swim. For more than a decade, neuroscientists and physiologists have been gathering evidence of the beneficial relationship between exercise and brainpower. But the newest Findings make it clear that this isn“t just a relationship; it is

3、the relationship. Using sophisticated technologies to examine the workings of individual neurons (神经元)and the makeup of brain matter itselfscientists in just the past few months have discovered that exercise appears to build a brain that resists physical shrinkage and enhance cognitive flexibility.

4、Exercise, the latest neuroscience suggests, does more to improve thinking than thinking does. B. The most persuasive evidence comes from several new studies of lab animals living in busy, exciting cages. It has long been known that so-called “enriched“ environmentshomes filled with toys and engaging

5、, novel taskslead to improvements in the brainpower of lab animals. In most instances, such environmental enrichment also includes a running wheel, because mice and rats generally enjoy running. Until recently, there was little research done to tease out the particular effects of running versus thos

6、e of playing with new toys or engaging the mind in other ways that don“t increase the heart rate. C. So, last year a team of researchers led by Justin S. Rhodes, a psychology professor at the Beckman Institute for Advanced Science and Technology at the University of Illinois, gathered four groups of

7、 mice and set them into four distinct living arrangements. One group lived in a world of sensual and taste plenty, dining on nuts, fruits and cheeses, their food occasionally dusted with cinnamon (肉桂), all of it washed down with variously flavored waters. Their “beds“ were small colorful plastic dom

8、e-shaped houses occupying one corner of the cage. Neon-hued (霓虹色的) balls, plastic tunnels, chewable blocks, mirrors and seesaws (跷跷板) filled other parts of the cage. Group 2 had access to all of these pleasures, plus they had small disc-shaped running wheels in their cages. A third group“s cages hel

9、d no decorations, and they received standard, dull food. And the fourth group“s homes contained the running wheels but no other toys or treats. D. All the animals completed a series of cognitive tests at the start of the study and were injected with a substance that allows scientists to track change

10、s in their brain structures. Then they ran, played or, if their environment was unenriched, stayed lazily in their cages for several months. Afterward, Rhodes“s team put the mice through the same cognitive tests and examined brain tissues. It turned out that the toys and tastes, no matter how stimul

11、ating, had not improved the animals“ brains. E. “Only one thing had mattered,“ Rhodes says, “and that“s whether they had a running wheel.“ Animals that exercised, whether or not they had any other enrichments in their cages, had healthier brains and performed significantly better on cognitive tests

12、than the other mice. Animals that didn“t run, no matter how enriched their world was otherwise, did not improve their brainpower in the complex, lasting ways that Rhodes“s team was studying. “They loved the toys,“ Rhodes says, and the mice rarely ventured into the empty, quieter portions of their ca

13、ges. But unless they also exercised, they did not become smarter. F. Why would exercise build brainpower in ways that thinking might not? The brain, like all muscles and organs, is a tissue, and its function declines with underuse and age. Beginning in our late 20s, most of us will lose about 1 perc

14、ent annually of the volume of the hippocampus (海马体), a key portion of the brain related to memory and certain types of learning. G. Exercise though seems to slow or reverse the brain“s physical decay, much as it does with muscles. Although scientists thought until recently that humans were born with

15、 a certain number of brain cells and would never generate more, they now know better. In the 1990s, using a technique that marks newborn cells, researchers determined during examining the dead bodies that adult human brains contained quite a few new neurons. Fresh cells were especially prevalent in

16、the hippocampus, indicating that neurogenesis (神经形成)or the creation of new brain cellswas primarily occurring there. Even more encouraging, scientists found that exercise jump-starts neurogenesis. Mice and rats that ran for a few weeks generally had about twice as many new neurons in their hippocamp

17、i as motionless animals. Their brains, like other muscles, were bulking up. H. But it was the indescribable effect that exercise had on the functioning of the newly formed neurons that was most startling. Brain cells can improve intellect only if they join the existing neural network, and many do no

18、t, instead existing aimlessly in the brain for a while before dying. One way to pull neurons into the network, however, is to learn something. In a 2007 study, new brain cells in mice became looped into the animals“ neural networks if the mice learned to navigate (导航) a water maze (迷宫), a task that

19、is cognitively but not physically taxing. But these brain cells were very limited in what they could do. When the researchers studied brain activity afterward, they found that the newly wired cells fired only when the animals navigated the maze again, not when they practiced other cognitive tasks. T

20、he learning encoded in those cells did not transfer to other types of rodent (啮齿动物) thinking. I. Exercise, on the other hand, seems to make neurons move quickly and easily. When researchers in a separate study had mice run, the animals“ brains readily wired many new neurons into the neural network.

21、But those neurons didn“t fire later only during running. They also lighted up when the animals practiced cognitive skills, like exploring unfamiliar environments. In the mice, running, unlike learning, had created brain cells that could multitask. J. Just how exercise remakes minds on a molecular le

22、vel is not yet fully under-stood, but research suggests that exercise prompts increases in something called brain-derived neurotropic factor (脑源性神经营养因子), or B. D. N. F., a substance that strengthens cells and axons (轴突), strengthens the connections among neurons and sparks neurogenesis. Scientists c

23、an“t directly study similar effects in human brains, but they have found that after physical exercise, most people display higher B. D. N. F. levels in their bloodstreams. K. Few if any researchers think that more B. D. N. F. explains all of the brain changes associated with exercise. The full proce

24、ss almost certainly involves multiple complex biochemical and genetic cascades (级联反应). A recent study of the brains of elderly mice, for instance, found 117 genes that were expressed differently in the brains of animals that began a program of running, compared with those that remained motionless, a

25、nd the scientists were looking at only a small portion of the many genes that might be expressed differently in the brain by exercise. L. Whether any type of exercise will produce these desirable effects is another unanswered and intriguing issue. “It“s not clear if the activity has to be endurance

26、exercise,“ says the psychologist and neuroscientist Arthur F. Kramer, director of the Beckman Institute at the University of Illinois and a celebrated expert on exercise and the brain. A limited number of studies in the past several years have found cognitive benefits among older people who lifted w

27、eights for a year and did not otherwise exercise. But most studies to date, and all animal experiments, have involved running or other aerobic (有氧的) activities. M. Whatever the activity, though, an emerging message from the most recent science is that exercise needn“t be exhausting to be effective f

28、or the brain. When a group of 120 older men and women were assigned to walking or stretching programs for a major 2011 study, the walkers wound up with larger hippocampi after a year. Meanwhile, the stretchers lost volume to normal shrinkage. The walkers also displayed higher levels of B. D. N. F. i

29、n their bloodstreams than the stretching group and performed better on cognitive tests. N. In effect, the researchers concluded, the walkers had regained two years or more of hippocampal youth. Sixty-five-year-olds had achieved the brains of 63-year-olds simply by walking, which is encouraging news

30、for anyone worried that what we“re all facing as we move into our later years is a life of slow mental decline. (选自 New Scientist)（分数：20.00）(1).Until recently, scientists thought that the number of brain cells was fixed.（分数：2.00）(2).By walking, the walkers could make hippocampus become two years or

31、more younger.（分数：2.00）(3).According to the latest neuroscience, physical training is more important to improve thinking.（分数：2.00）(4).Scientists have found higher levels of B. D. N. F. in the bloodstreams after people doing exercises.（分数：2.00）(5).The research of Justin S. Rhodes showed that the mice“

32、s brains were improved only by running wheels.（分数：2.00）(6).Besides learning, hippocampus also has something to do with memory.（分数：2.00）(7).Compared with the stretchers, the walkers passed cognitive tests with better performance.（分数：2.00）(8).The 2007 study showed the water maze navigation by mice cou

33、ld connect their new brain cells to the neural networks.（分数：2.00）(9).In Justin S. Rhodes“ research, the third group of mice had standard foods.（分数：2.00）(10).According to Arthur F. Kramer, it“s uncertain whether the effective brain activity has to be endurance exercise.（分数：2.00）Nine Most Amazing Goog

34、le Search TricksA. Searching on Google can be a magical experience once you find out how to make your search queries efficient. By making efficient I mean using some tricks or the cheat sheet provided by Google itself to quickly find what you actually require. Having being hooked onto Google for a l

35、ong time now, I have come across some amazing search tricks which can change the way you look at Google today. In this article I will list down the search tricks which I use quite frequently. Be it finding time, meanings or watching the cricket score, searching PDF“s, with Google as the search engin

36、e life cannot be simpler. Here are the nine most amazing Google Search tricks: Different types of files at your will B. How many times would you have asked for materials (PDF, PPT, DOC) for a particular topic from a friend? It“s almost everyday that we might have the necessity to ask them either for

37、 knowledge, preparing a presentation, white-paper or for case studies. Such times it mostly difficult to look out what to exactly search for because most of the times you don“t know about the topic at hand. But this petty keyword unleashes its lethal power at such occasions. Let“s say I want to impl

38、ement a case study on SOA which means I have to read a lot of information for SOA. So I just have to find materials which might have already been uploaded on the web in the form of PDF“s, DOC“s or PPT“s. These materials can be easily obtained by doing a search for: * PDFservice oriented architecture

39、 file-type: pdf * PPTservice oriented architecture file-type: ppt * DOCservice oriented architecture file-type: doc Scholarly search C. If you want some authenticity of the materials then it would be better to find the materials from educational institutes or universities. For this use the Google sc

40、holar search. But suppose you don“t like to switch to Google scholar search you can add the same query with an additional parameter to the normal Google search box. * service oriented architecture file-type: pdf site: edu Meanings of any word in an instant D. Now you do not have to carry a dictionar

41、y or install a dictionary software just for the purpose of finding out a meaning of a word. With the wealth of information in Google“s hands, it“s a piece of cake to find out the meaning of the word. Just use the define: keyword. The meaning would of course be displayed but also a set of other links

42、 which might have an alternative definition are also given out with the link to read more about it. * define: bureaucracy E. You would argue here that, a dictionary gives out more information than this. But what about words that don“t actually fall within the vocabulary. Suppose you want to know wha

43、t SOA (Service Oriented Architecture) is then you would have no choice. Google Search comes to your rescue in this case, * Abbreviationsdefine: SOA * Jargons (术语)define: Web 2.0 * SMS languagedefine: LOL Find the time of any location F. Many of us might be probably working for client which are based

44、 at different locations. And communication has to be carried out frequently in such cases. But before a communication you have to know which time zone the location is falling into otherwise you would be causing a disturbance. I have seen people installing time zone software for showing the time of t

45、he location they would be calling to. But with Google at your hands you don“t have to install any software. It would be just simple to use a query for finding the current time such as, * time new york psst.look closely the time on the little clock graphic. It also shows the perfect time! Weather at

46、your fingertips G. I had been to GOA for a Christmas vacation in the last week of December. But I made a mistake of not finding out the temperature of GOA before leaving. Had I known that it is hot even in the winter I would not have made the mistake of carrying additional luggage consisting of blan

47、kets and jackets. If you are thinking to visit a place it is useful to know what the temperature of the place is before hand, it can make efficient packing. Google helps you here too. Just use this query without asking anybody or waiting for the news to make a weather report. I wish I had thought of

48、 this! * goa weather Google does live commentary tool H. Indians are cricket fanatics. But it“s amusing to see the organizations here trying to put together tactics to devoid cricket lovers from wasting time to watch the cricket scores instead of doing their work. What I think they fail to understan

49、d is that by blocking the live cricket scoring sites they are actually making the employees more curios and provoking them to hunt for proxy networks or listen to the radio or chat with their friends elsewhere. Jokes apart, you actually don“t need proxy networks to view the live cricket scores if you at least have access to Google. If you want to find the latest info about all the cricket matches then just type, * cricket But if you want to find out only about a particular match then use only the names of the two playing nations, * India Australia Calculate with your browser I. Eve