大学英语四级试卷模拟一试卷答案对照版
Questions 1 to 5 are based on the following passage:
It was once believed that being overweight was healthy, but nowadays few people subscribe to this viewpoint. While many people are fighting the battle to reduce weight, studies are being conducted concerning the appetite and how it is controlled by both emotional and biochemical factors. Some of the conclusions of these studies may give insights into how to deal with weight problems. For example, when several hundred people were asked about their eating habits in times of stress, 44 percent said they reacted to stressful situations by eating. Further investigations with both humans and animals indicated that it is not food which relieves tension but rather the act of chewing.
A test in which subjects were blindfolded showed that obese(肥胖)people have a keener sense of taste and crave（渴望） more flavorful food than non-obese people. When deprived of the variety and intensity of tastes, obese people are not satisfied and consequently eat more to fulfill this need. Blood samples taken from people after they were vaguely
shown a picture of food revealed that overweight people reacted with an increase in blood insulin（胰岛素）, a chemical associated with appetite. This did not happen to average-weight people.
In another experiment, results showed that certain people have a
specific, biologically induced hunger for carbohydrate（糖类）.
Eating carbohydrates raises the level of serotonin, a neurotransmitter in the brain. Enough serotonin produces a sense of satiation（满足),and hunger for carbohydrates subsides.
Exercise has been recommended as an important part of a weigh-loss program. However, It has been found that mild exercise, such as using the stairs instead of the elevator, is better in the long run than taking on a strenuous program, such as jogging, which many people find difficult to continue over long periods of time and which also increase appetite.
1. It can be inferred from the passage that _______.
A) overweight people are tense
B) thin people don't eat when under stress
C) weight watchers should chew on something inedible when tense
D) 56 percent of the population isn't overweight.
2. According to the passage, insulin _______.
A) increases in the bloodstream when people eat large amounts of food
B) can be used to lessen the appetite
C) causes a chemical reaction when food is seen
D) levels don't change in average-weight people who see food
3. In order to lose weight, it would be a good idea for heavy people to _______.
A) jog 3 miles daily and chew on carrot sticks
B) avoid stressful situations and have control over their eating habits
C) eat plenty of chewy carbohydrates
D) walk up stairs and look at pictures of food
4. Which of the following exercises might be best for an overweight person to engage in daily?
A) An evening walk
B) A long swim
C) Cross-country skiing
D) 10-mile bicycle rides
5. What can be said about serotonin?
A) It is a chemical that increases the appetite.

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