问题补充：
During the day we work and play，and at night we sleep. Our body rests when we sleep. In the morning we are ready to work and play again. Our body grows most when we are asleep. Children who are tired usually need sleep. We can get better at our lessons after having plenty of rest. Boys and girls who are eight or nine years old need ten hours of sleep every night. Our body needs plenty of air when we are asleep. If we do not get enough fresh air, we will feel tired when we wake up. While in bed we must not cover(覆盖) our head，our lungs need to get enough fresh air. If we open our windows at night，we can have plenty of fresh air. Cool air is better than warm air.
【小题1】Our body grows most while we are .
A.eating B.playing C.sleeping
【小题2】Too little sleep makes us .
A.tired B.hungry C.happy
【小题3】—What may cause us to feel tired in the morning?
— during the sleep.
A.Too much air B.Not enough fresh air
C.Too much cold air
【小题4】How many hours of sleep should 9-year-old children have every night?
A.8 hours. B.9 hours. C.10 hours.
【小题5】What do the lungs need most?
A.Fresh air. B. Exercise. C.Warm air.C
答案：
(答案→)C
解析：
【小题1】根据Our body grows most while we are asleep.描述可知选C。
【小题1】根据If we do not get enough fresh air, we will feel tired when we wake up.及上文描述可知如果睡眠不足可导致劳累，故选A。
【小题1】根据If we do not get enough fresh air, we will feel tired when we wake up.可知选B。
【小题1】根据Boys and girls who are eight or nine years old need ten hours of sleep every night.描述可知选C。
【小题1】根据Our lungs need to get enough fresh air.描述可知选A。
