B

    Everyone must go to bed early and get up early, or we won't be healthy and clever

    Is this true? Perhaps it is. The body must have enough sleep. The students aged 8—18 need ten hours' sleep every day. If you don^ go to bed early, you won't have enough sleep. Then you can't think properly and do your work properly. You'll not be clever.

    Some people go to bed late and get up late. This is not good for them. We must sleep at night when it is dark. The dark helps us to sleep soundly. When the daytime comes, we must get up. This is the time for exercise. If you lack exercise, the body will become weak. Exercise keeps a strong body.

    Exercise helps the blood (血液）flow(流动）around inside the body. This is very important. Blood takes food to all parts of our bodies. The brain also needs blood. We think with our brains. If we keep our body healthy and take exercise, we can think better.