Early to bed, early to rise, makes a man healthy, wealthy and wise． This is an old English saying．Have you heard of it before? It means that we must go to bed early and get up early in the morning．Then we shall be healthy． We shall also be rich （wealthy） and clever（wise）．
This is true． The body must have enough sleep to be healthy．Children of young age should have ten hours’ sleep every night．Children who do not have enough sleep cannot do their work very well．They will not be wise and they may not become wealthy.
The body also needs exercise．Walking, running, jumping, swimming and playing games are all exercise．Exercise keeps the body strong．
Exercise also helps the blood（血液） to move around inside the body．This is very important．Our blood takes food to all parts of our body． The head also needs blood．Exercise helps us to think better.
回答下列各题。
How can we be healthy?
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What will happen if a child doesn’t have 10 hours’ sleep?
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Why does a person need exercise?
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What will happen to your blood if you take exercise?
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What’s the passage about?
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