Good health is very important. Everyone should do all he can to stay healthy. Being in good health means having both body and mind in good order, free from illness and pain. Good food, plenty of water, cleanness and plenty of rest all help in keeping our machines running as they should. Food does many things for our bodies. It gives what we need for keeping good health. It gives us energy for work and play. No food gives everything we need. We should eat foods of different kinds. Having enough to eat is not the same as having the right food. The water we drink helps wash away wastes formed inside our bodies. It also puts back the water we lose when we perspire(流汗). Our bodies are actually more than half water. We must drink enough to replace what we lose. We feel better and look better when we are clean. A bath every one or two days is a good rule for most of us. Brushing our teeth is important part of keeping clean. Sleep is the best kind of rest. Growing children need more sleep than grown-ups. Children's bodies not only have to be repaired; they also have to grow, No one's body can grow bigger properly while he is working and playing and wearing it out (疲劳). It has been useful to work for good health. Millions of years ago, people live only 20 years. Now people can live about 70 years. It has gone up 20 years just since the beginning of the present century. 小题1: You should have foods of different kinds because _________. A．some foods are not good B．no food can give everything you need C．different foods taste different D．different people like different foods 小题2: We must drink enough water to replace what we lose. Here replace means . A．感觉 B．放置 C．减少 D．代替 小题3: At the beginning of the present century people live about _________. A．20 years. B．70 years C．40 years D．50 years 小题4: Which of the following is NOT true? A．Grown-ups sleep less than children because they have a lot of work to do. B．If one's mind does not work well, he is not considered to be healthy. C．One cannot grow well when he works too hard. D．About half of man's body is water.