During the day we work and play, and at night we sleep. Our body has a rest while we are sleeping. Then we can work and play a during the whole day.

    Our body is the best while we are sleeping. Children who are tired usually need more sleep. Boys and girls who are eight or nine years old need ten h of sleep every night.

    What's more(而且),our body needs lots of air w we sleep. If we don't get enough air, we will feel tired after waking up in the morning. While in bed we mustn't cover(盖住) our heads. Our lungs(肺) need to get enough fresh air. If we o our windows at night, we can have enough fresh air, Cool air is b than warm air. If boys and girls want to be strong, they should get lots of sleep with fresh air.