20、Class，you know during the day we work and play，at night we sleep．Our bodies rest while we sleep．In the morning we are ready to work and play again．While we are sleeping，our bodies grow most．When we are tired，we need more sleep．We can get our lesson better and we will feel better，too，when we have enough rest．A nine-year-old child needs ten hours of sleep every night．Our bodies need a lot of air when we sleep．If we do not get enough fresh air，we'll feel tired when we get up．While in bed we must not cover our heads．If we do，our lungs will not get enough fresh air．If we open our windows at night，we can have lots of fresh air．Cool air is better than warm air．If boys and girls want to grow and be strong，they must get enough sleep．

1．Our bodies grow most while we are ________．

A．sleeping          B．playing                  C．having sports          D．eating much

2．Which is the best air for our sleep?

A．Hot air                  B．Cool air．               C．Warm air．             D．Dry air．

3．If a boy has six hours of sleep，he will ________．

A．get his lesson better                                    B．feel better

C．feel tired                                                   D．grow fast

4．What does the underlined word “lungs” mean in Chinese?

A．气管                   B．心脏                     C．肺                       D．肝

5．From the passage，He know that ________．

A．enough sleep makes our bodies strong and grow most

B．boys and girls need nine hours of sleep

C．the more we sleep，the more tired we feel

D．we should close the window while sleeping