[外语类试卷]大学英语四级改革适用(阅读)模拟试卷228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 228及答案与解析 Section C 0 How does food affect mood and mind? The answer may lie in the chemistry of the brain and nervous system. Molecules called neurotransmitters (神经传递素 ) are chemical messengers. They carry a nerve impulse across the gap between nerve cells. The release of neurotr
2、ansmitter molecules from one neuron and their attachment to receptor sites on another keep a nerve impulse moving. Nerve impulses carry messages from the environment to the brain, for example, the pain you feel when you stub (踢碰 ) your toe. They also carry messages in the other direction, from the b
3、rain to the muscles. Thats why you back away from the obstacle that initiated the pain signal and exclaim, “Ouch! “ “Many neurotransmitters are built from the foods we eat,“ says neuroscientist Eric Chudler of the University of Washington. Too little or too much of a particular nutrient in the diet
4、can affect their production, Chudler says. For example, tryptophan from foods such as yogurt, milk, bananas, and eggs is required for the production of the neurotransmitter serotonin. Phenylalanine from beets, almonds, eggs, meat, and grains goes into making the neurotransmitter dopamine. Dozens of
5、neurotransmitters are known; hundreds may exist. Their effects depend on their amounts and where they work in the brain. The neurotransmitter serotonin, for example, is thought to produce feelings of calmness, relaxation, and contentment. Drugs that prevent it from being taken again (into the neuron
6、 that released it) are prescribed to treat depression. In at least some healthy, nondepressed people, carbohydrate foods seem to enhance serotonin production and produce similar effects. “It is the balance between different neurotransmitters that helps regulate mood,“ Chudler says. Proper nutrition
7、may also enhance brainpower. Choline is a substance similar to the B vitamins. Its found in egg yolks, whole wheat, peanuts, milk, green peas, liver, beans, seafood, and soybeans. The brain uses it to make the neurotransmitter acetylcholine. To test the effects of choline on memory and learning, res
8、earchers at the Massachusetts Institute of Technology gave memory tests to college students before increasing the amount of choline in their subjects diets. Later, they retested. On the average, memories were better, and the students learned a list of unrelated words more easily. 1 The function of n
9、eurotransmitters can be best compared to that of_. ( A) a transport vehicle ( B) a protective shield ( C) a power plant ( D) a food factory 2 According to the second paragraph, messages sent from the brain to the muscles make you_. ( A) feel the pain ( B) stub your toe ( C) see an obstacle ( D) excl
10、aim “Ouch“ 3 When is depression resulted? ( A) When the level of serotonin is low. ( B) When the level of serotonin is high. ( C) When serotonin is released from neurons. ( D) When people eat carbohydrate foods. 4 Researchers at the Massachusetts Institute of Technology intended to find out_. ( A) h
11、ow choline is produced out of foods ( B) how choline is converted into acetylcholine ( C) if the improvement of brainpower is related to choline ( D) if the improvement of brainpower is related to proper diets 5 What is the message the author intends to convey? ( A) The chemistry of the brain and ne
12、rvous system. ( B) The influence of foods on our mood and mind. ( C) The functions of neurotransmitters. ( D) The importance of a balanced diet. 5 Like a needle climbing up a bathroom scale, the number keeps rising. In 1991, 15% of Americans were obese (肥胖的 ); by 1999, that proportion had grown to 2
13、7%. Youngsters, who should have age and activity on their side, are growing larger as well: 19% of Americans under 17 are obese. Waistbands have been popping in other western countries too, as physical activity has declined and diets have expanded. By and large, people in the rich world seem to have
14、 lost the fight against flab (松弛 ). Meanwhile, poorer nations have enjoyed some success in their battles against malnutrition and famine. But, according to research presented at the annual meeting of the American Association for the Advancement of Science, it is more a case of being out of the fryin
15、g pan and into the fire. The most striking example actually in the poor world comes from the Pacific islands, home of the worlds most obese communities. In 1966, 14% of the men on this island were obese while 100% of men under the age of 30 in 1996 were obese. This increase in weight has been uneven
16、 as well as fast. As a result, undernourished and over-nourished people frequently live cheek by jowl (面颊 ). The mix can even occur within a single household. A study of families in Indonesia found that nearly 10% contained both the hungry and the fat. This is a mysterious phenomenon, but might have
17、 something to do with people of different ages being given different amounts of food to eat. The prospect of heading off these problems is bleak. In many affected countries there are cultural factors to contend with, such as an emphasis on eating large meals together, or on food as a form of hospita
18、lity. Moreover, there is a good measure of disbelief on the part of policymakers that such a problem could exist in their countries. Add to that reluctance on the part of governments to spend resources on promoting diet and exercise while starvation is still a real threat, and the result is a recipe
19、 for inaction. Unless something is done soon, it might not be possible to turn the clock back. 6 The first sentence of the passage most probably implies that_. ( A) many Americans are obsessed with the rising temperature in their bathroom ( B) more people are overweighed in the United States ( C) pe
20、ople are doing more physical exercises with the help of scales ( D) youngsters become taller and healthier thanks to more activities 7 As physical exercise declines and diet expands, _. ( A) other western countries has been defeated by fat ( B) obesity has become an epidemic (流行病 ) of the rich world
21、 ( C) waistbands begin to be popular in other western countries ( D) western countries can no longer fight against obesity 8 Which is NOT the point of the example of the Pacific Islands? ( A) The poor community has shaken off poverty and people are well-fed now. ( B) Obesity is becoming a problem in
22、 the developing world too. ( C) Excessive weight increase will cause no less harm than the food shortage. ( D) The problem of overweight emerges very fast. 9 Of tackling obesity in the poor world, we can learn from the passage that _. ( A) the matter is so complex as to go beyond our capacity ( B) n
23、o matter what we do, the prospect will always be bleak ( C) it is starvation, the real threat, that needs to be solved ( D) we should take immediate actions before it becomes incurable 10 What is the main idea of this passage? ( A) Obesity is now a global problem that needs tackling. ( B) The weight
24、s increase fast throughout the whole world. ( C) Obesity and starvation are two main problems in the poor world. ( D) Obesity has shifted from the rich world to the poor world. 10 On a more mundane (世俗的 ) level, third-generation mobile telephones, despite all the delays and the billions squandered o
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- 外语类 试卷 大学 英语四 改革 适用 阅读 模拟 228 答案 解析 DOC
