1、 阅读文章，选择正确答案，回答问题。More and more scientific experiments prove that physical exercise can reduce the danger of some illnesses in middle-aged persons. Exercise strengthens the heart muscle, reduces blood pressure and helps to prevent muscles from changing into fat. Physical exercise is just as importan
2、t for children.Exercise and food affect growing speed in young lab animals. Baby mice start running as soon as they are big enough to use an exercise wheel in their cage. If they get extra food and run a lot, they will grow as much as 1.5 times bigger than normal.The same differences in growing spee
3、d might be found between active and inactive children. Physical exercise helps active children grow faster than inactive children. One experiment shows that the brains of the mice that had enough exercise weighed about 3% more than those of the mice that did not exercise. The mice that exercised are
4、 much quicker to learn doing new exercise than the mice that did not exercise.The result of the experiments support the theory that exercise can help babies learn to talk and walk sooner than expected. The good efforts of physical exercise are not limited to children and middle-aged people. Exercise
5、s continue to be an important part of our lives after we grow old. For example, people over 50 years old begin to lose calcium(钙) in their bones, which get weaker and can break easily. Physical exercise, however, helps to strengthen the bones and to prevent them from losing calcium. Of course, old p
6、eople can take medicines to prevent themselves from suffering from losing calcium, but the medicines they take increase the chance of developing some kind of cancer. So physical exercise is a much safer means of treatment.1. This passage tells that _.A. only middle-aged persons can benefit from phys
7、ical exerciseB. physical exercise can do good to both the middle-aged and childrenC. people of different ages can all benefit from physical exerciseD. physical exercise is the safest treatment for losing calcium2. Active children _ than inactive children.A. are cleverer and healthierB. are clever bu
8、t not strongerC. are stronger but some foolishD. enjoy walking more3. From the passage we know that _.A. mice need to eat more and exercise moreB. children need more exercise than other peopleC. old people like to take medicine to treat their illnessD. middle-aged people are easy to get fat4. The bones of old people are easy to break because_.A. there is less calcium in their bones than in those of other peopleB. they are easy to become illC. they eat less than other peopleD. they have less exercise than other people答案：1. C2. A3. D4. A
