阅读理解
Everyone knows that exercise is important. We all need to exercise. Doctors say it's good for us. It keeps body strong.
When the daytime comes, we must get up. This is the time for exercise. Exercise means doing things with the body. There're many ways to exercise. You can walk, run, swim, skate, or play ball games. Make sure you exercise in the following(下面的)ways: You have to like what you're doing. Exercise enough—but not too much. It's good to exercise twice each week. Thirty minutes each time is enough. Try all kinds of things until you find one, two or three sports that feel right for you.
Exercising can be fun. Friends can exercise together at a fitness center, or they can play sports together. How do you exercise?
根据短文内容，选择正确答案。
