During the day we work and play, and at night we sleep. Our body rests while we sleep .In the morning we are ready to work and play again. Our body grows most while we are asleep. Children who are tired usually need sleep. We can get better at our lessons after we have had 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 sleep. If we do not get enough fresh air, we will feel tired when we wake up. While in bed we must not cover 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.Boys and girls who want to be strong must get enough and plenty of sleep.
小题1:Our body grows most while we are.
A．eating
B．playing
C．sleeping
D．exercising小题2:Too little sleep makes us
A．tired
B．hungry
C．happy
D．grow小题3:.What may cause us to feel tired in the morning?
A．Too much air
B．Not enough fresh air
C．Too much cold air
D．Too much sleep小题4:How many hours of sleep should nine-year-old children have ?
A．Eight hours
B．Nine hours
C．Ten hours
D．Eleven hours小题5:What does the lung need most ?
A．Fresh air
B．Covering
C．Warm air
D．Exercise
=1×10-8,下列叙述不正确的是( )
)+c(H+)=c(Cl-)+c(OH-)
)