已知x，y＞0，且x+4y=1，则1x+1y的最小值为______．
题型：填空题
问题：
已知x，y＞0，且x+4y=1，则
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题型：填空题
Enough sleep is important to health. The amount o f 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 judgement to satisfy his need. Sleep should always be enou
gh 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 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.
小题1:How many hours are usually enough for the health of a pupil?
A．Less than eight hours.
B．No more than eight hours.
C．Eight hours or so.
D．No less than eight hours.小题2: Which of the following is helpful to good sleep?
A．Keeping good habits.
B．Staying up late at night.
C．Eating something at bedtime.
D．Forming the habit of taking sleep-producing drug.小题3: The amount of sleep a person needs has something to do with________.
A．his age
B．his height
C．his weight
D．his character小题4:Before going to bed, you’d better not_______.
A．take a bath
B．do any housework
C．think a lot
D．go out for relaxation