大学四级-1406及答案解析.doc
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1、大学四级-1406 及答案解析(总分:712.00,做题时间:90 分钟)一、Part Writing(总题数:1,分数:106.00)1.简述一次与朋友或同学难忘的野餐2描述当时野餐的情况3谈谈自己的感受和体会An Unforgettable Picnic(分数:106.00)_二、Part Reading Compr(总题数:1,分数:70.00)How Exercise Makes You SmarterExercise does more than build muscles and help prevent heart disease. New science shows that
2、it also boosts brainpower-and may offer hope in the battle against Alzheimer(痴呆症).The stereotype of the “dumb jock“ has never sounded right to Charles Hillman. A jock himself, he plays hockey four times a week, but when he isnt body-checking his opponents on the ice, hes giving his mind a comparable
3、 workout in his neuroscience and kinesiology lab at the University of Illinois. Recently he started wondering if there was a vital and overlooked link between brawn and brains-if long hours at the gym could somehow build up not just muscles, but minds. With colleagues, he started an experiment. He r
4、ounded up 259 Illinois third and fifth graders, measured their body-mass index and put them through classic PE routines: the “sit-and-reach“, a brisk run and timed push-ups and sit-ups. Then he checked their physical abilities against their math and reading scores on a statewide standardized test. S
5、ure enough, on the whole, the kids with the fittest bodies were the ones with the fittest brains, even when factors such as socioeconomic status were taken into account. Sports, Hillman concluded, might indeed be boosting the students intellect.Hillmans study, which will be published later this year
6、, isnt definitive enough to stand alone. But it doesnt have to: it is part of a recent and rapidly growing movement in science showing that exercise can make people smarter. Other scientists have found that vigorous exercise can cause nerve cells to form dense, interconnected webs that make the brai
7、n run faster and more efficiently. And there are clues that physical activity can stay away from the beginnings of Alzheimers disease, ADHD and other cognitive disorders. No matter your age, it seems, a strong, active body is crucial for building a strong, active mind.Some scientists have always sus
8、pected as much, although they have not been able to prove it. Now, however, armed with brain-scanning tools and a sophisticated understanding of biochemistry, researchers are realizing that the mental effects of exercise are far more profound and complex processes than they once thought. The process
9、es start in the muscles. When the exercise is available, the muscle sends out chemicals, including a protein called IGF-1 that travels through the bloodstream, across the blood-brain barrier and into the brain itself. And then the brain issues orders fuels almost all the activities that lead to high
10、er thought.With regular exercise, the body builds up its levels of BDNF, and the brains nerve cells start to branch out, join together and communicate with each other in new ways. This is the process that underlies learning: every change in the junctions between brain cells signifies a new fact or s
11、kill thats been picked up for future use. BDNF makes that process possible. Brains with more of it have a greater capacity for knowledge. On the other hand, says UCLA neuroscientist Fernando G6mez-Pinilla, a brain thats low on BDNF shuts itself off to new information.Most people maintain fairly cons
12、tant levels of BDNF in adulthood. But as they age, their individual neurons (神经)slowly start to die off. Until the mid-90s, scientists thought the loss was permanent-that the brain couldnt make new nerve cells to replace the dead ones. But animal studies over the last decade have overturned that ass
13、umption, showing that “neurogenesis“ (神经发生)in some parts of the brain can be induced easily with exercise. Last weeks study, published in the Proceedings of the National Academy of Sciences, extended that principle to humans for the first time. After working out for three months, all the subjects ap
14、peared to regain new neurons. This, too, might be BDNF at work, transforming stem cells into full-grown, functional neurons. “It was extremely exciting to see this exercise effect in humans for the first time,“ says Scott Small, a Columbia University Medical Center neurologist who coauthored the stu
15、dy with Salk Institute neurobiologist Fred Gage. “In terms of trying to understand what it means, the field is just exploding.“As far as scientists know, the new neurons created by exercise are produced in only one place: the dentate gyrus, an area that controls learning and memory. This region help
16、s the brain match names to faces-one of the first skills to erode as we age. New neurons cant grow throughout the rest of the brain. But other regions benefit from exercise in many secondary ways. Blood volume, like brain volume, increases with exercise. Active adults have less inflammation in the b
17、rain. They also have fewer “little possibility of strokes that can impair cognition without the person even knowing,“ says Kristine Yaffe, a neuroscientist from University of California. Still other researchers have found that athletes have more cells that support neurons and increase neurotransmitt
18、ers after theyre used to send messages from cell to cell. And even the levels of those neurotransmitters are higher in people who exercise frequently.Unlike neurogenesis, which can take weeks to occur, most of these additional effects appear almost immediately. Get off the treadmill (踩单车) after a ha
19、lf-hour workout, says Hillman, and “within 48 minutes“ your brain will be in better shape. But alas, these benefits are somewhat transient(短暂的). Like weight, mental fitness has to be maintained. New neurons, and the connections between them, will stick around for years, but within a month of inactiv
20、ity, “it will shrink down, and then the neurons dont function as well anymore,“ says William Greenough, a psychologist at the University of Illinois. Let your body go, then, and your brain will follow.To keep the effects, youve got to keep working out. “If youre thinking that by exercising at age 20
21、 youre going to have some effect on what youre like at age 70,“ Greenough adds, youd better be willing to commit to 50 years of hitting the gym. Unless, that is, youre a kid. Most studies of exercise and cognition have focused on older people-the folks who are just starting to worry that their minds
22、 arent what they used to be-but the effects of physical exertion on the brain arent limited to that group at all. In fact, in young children, theyre even more potent. Exercise probably has “a more long-lasting effect on brains that are still developing,“ says Phil Tomporowski, a professor of exercis
23、e science at the University of Georgia. In kids, as in adults, the brain reaps many benefits from exercise. This wont surprise parents of kids with ADHD, many of whom already use physical activity as a substitute or supplement for drugs.(分数:70.00)(1).What is the new benefit of exercise found by thos
24、e scientists?(分数:7.00)A.It can build muscles.B.It can prevent heart disease.C.It can keep people healthy.D.It can improve brainpower.(2).Whats the conclusion that Charles Hillman got from his experiment?(分数:7.00)A.Exercise can keep students healthy.B.Exercise can improve students brainpower.C.Exerci
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- 大学 1406 答案 解析 DOC
