Before you read：
　　Look up the word exercise in a dictionary. What does it mean？
　　Why do you need to exercise？
　　Exercise is good for you because it can help you to keep fit and healthy. It is not      enough just to eat a healthy diet1. Exercise is important too. Exercise will make your muscles2 stronger. There are about 600 muscles in the body. They move your bones3 and let you move your joints4. If you do not exercise your muscles， they will be weaker and smaller.
　　One of the most important muscles in the body is the heart5. To exercise your heart， you need to do something like swimming， or playing a game in which you run about. This will make you breathe more deeply and make your heart and lungs6 stronger.
　　One of the places where you can exercise is at school. In school， children have PE lessons and the lessons help them to keep fit and well. Try to exercise at least three times a week because exercise is good for you！
　　Exercise：
　　A. Complete these sentences. （補全下列句子。）
　　1. Exercise will make your muscles ____.
　　2. There are about ___ muscles in the   body.
　　3. One of the most important muscles in the body is the ____.
　　B. Answer the following questions. （回答下列问题。）
　　1. What does this passage talk about？
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　　2. Why is exercise good for you？
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　　3. What will happen to your muscles if you do not exercise？
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　　4. What  move  your  bones  and let you move your joints？
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　　5. What exercises does the writer say are good for the heart？
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　　6. What kind of exercise do you do in school？
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