第二部分 阅读理解（共25小题。第一节每小题2分，第二节每小题1分；满分45分
第一节  阅读下列短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项，并在答题卡上将该项涂黑
Animals seem to have the sense to eat when they are hungry and they do not eat more than their bodies need. It has been demonstrated （证明） that rats will , when given a choice over a period of time, prefer water with vitamins to water without vitamins, even though there is no difference in taste or smell between the two water bottles. When a fragrant （芳香的）flavor was added to the vitamins enriched fluid（液体），the rats did seem to develop a taste for it and kept drinking it , even after the vitamins were changed to the clear water. In time, however, they broke the habit and went back to where the necessary vitamins were.
In a classic experiment, babies of 6 to 12 months old were placed in a cafeteria（自助餐厅） feeding arrangement, with a wide choice of baby food before them. They were given whatever food they pointed to or appeared interested in. We are told that at first they showed some unusual eating patterns, but that over a period of time they managed to choose a well-balanced diet.
So in choosing food rats and babied do seem to know and act on what’s best for them. Obviously, there is a kind of “body wisdom”, which humans soon lose. Most of us do not eat as determined and influenced by long established（建立的） habits. Some people eat foxes, dogs and blackbirds, while we eat cows and pigs. So what people eat and how much they eat seems to be greatly influenced by what is going around them.
1. In the experiment on rats, a fragrant flavor was added to the rat’s drinking water to _______
A. encourage rats to drink vitamin-enriched water
B. find out rats’ preference in flavor
C. test whether rats know which drink is food for them
D. demonstrate that vitamins are tasteless
2. As far as their eating habits are concerned, babies and rats are similar in that _______
A. both have the wisdom to choose a balanced diet
B. both prefer flavored food and drink
C. both have the same eating patterns
D. both develop a taste for the same kinds of flavors
3. In the classic experiment mentioned in the second paragraph, babies were ________
A. given many choices of drinks
B. provided with various kinds of baby food
C. placed and fed in a cafeteria
D. trained to select a balanced diet
4. According to the passage, adults’ eating habits differ from those of babies because_______
A. adults know better than babies what kinds of food are good for their health
B. adults usually cannot resist the temptation of various delicious foods
C. adult’s eating habits are closely related to the social and cultural customs
D. adults have more choices of food than babies in eating patterns