单词填空。 Everyone knows that exercise is important. We all need to exercise. Doctors say i_____ (1) is good for us. It makes your heart and body s (2). Children who often exercise are more alert (灵活的). This means they do better in tests and schoolwork than those who don't exercise. There are many w (3) to exercise. You can walk, run, swim, skate, or play ball games. Make sure you e (4) in the following ways: you have to like what you're doing. Exercise enough - but not too m (5). It's best to exercise t (6) each week. Thirty minutes each time is enough. Try all kinds of things until you find one, two or even three sports that feel r (7) for you. You can exercise at fitness centers (健身中心). They have l (8) of equipment (设备) there. The equipment will help exercise your arms, legs and other parts of your body to make you f (9). Some people buy equipment for their homes. But it is very expensive. Exercising can be fun. Friends can exercise t (10) at a fitness center, or they can play sports together. How do you exercise?