Enough sleep is important to health. The amount of sleep needed depends on the age of the person and the conditions in which sleep takes place. The young may need more sleep than the old, but usually eight hours are enough for the health of grown-ups. Some can do with less than this amount, but others may need more. Every person knows his own need. It is then a matter of good judgment(判断) to satisfy his need. Sleep should always be enough to make one bring back his strength and get ready for a day’s work.
Fresh air is necessary to sound sleep. It is not without reason for some people to think that it is practicable to sleep in the open air. When one can keep himself warm, out-of-door sleeping probably gives the body its most complete relaxation(松弛).
Ability(能力) to sleep is largely a habit. The conditions referred to only lead to sleep. Out-of-door exercises, a good habit of regular hours and the avoidance(避免) of late eating and worry, which are largely within the control of any person, are all helpful to sound sleep.
A bath at bedtime, neither hot nor cool but of body temperature, may be helpful to sleep. Sleep-producing drug(药) should never be taken except when suggested by a doctor.
We know from the passage     is enough for the health of a pupil.

A．equal or more than eight hours	B．seven hours or so
C．Eight hours or so	D．Less than eight hours

If you want to have a good sleep,       is helpful.

A．forming the habit of taking sleep-producing drug.

B．keeping good habits.

C．staying up late night.

D．eating something at bedtime.

The amount of sleep a person probably needs has something to do with    .

A．his character

B．his control

C．his age

D．his habit

Before going to bed, you’d better not    .

A．take a bath	B．do any housework
C．go out for relaxation	D．think a lot