1.C sleeping
答案可从文中句子找到：Our body grows most when we are asleep .
2.A tired
文中的句子Children who are tired usually need sleep.累透的的孩子通常需要睡眠,也就是说缺少睡眠会让人容易累.
3.B Not enough fresh air.
答案可从文中句子找到：If we do not get enough fresh air ,we will feel tired when we wake up
4.C 10 hours
答案可从文中句子找到：Boys and girls of eight or nine years old need ten hours of sleep every night
5.A Fresh air
答案可从文中句子找到：While in bed we must not cover (覆盖)our head ,our lungs need to get enough fresh air .