[不定项选择题]共用题干 第二篇

Sleep Deficit

Judging from recent surveys,most experts in sleep behavior agree that there is virtually an epidemic（流
行病）of sleepiness in the nation."I can't think of a single study that hasn't found Americans getting less
sleep than they ought to,"says Dr. David.Even people who think they are sleeping enough would probably
be better off with more rest.
The beginning of our sleep-deficit (睡眠不足）crisis can be traced to the invention of the light bulb a
century ago.From diary entries and other personal accounts from the 18th and 19th centuries,sleep scien-
tists have reached the conclusion that the average person used to sleep about 9.5 hours a night."The best
sleep habits once were forced on us,when we had nothing to do in the evening down on the farm,and it was
dark."By the 1950s and 1960s,that sleep schedule had been reduced dramatically,to between 7.5 and 8
hours,and most people had to wake up to an alarm clock."People cheat on their sleep,and they don't even
realize they're doing it,"says Dr. David."They think they're okay because they can get by on 6.5 hours,
when they really need 7.5,eight or even more to feel ideally vigorous.
Perhaps the most merciless robber of sleep,researchers say,is the complexity of the day.Whenever
pressures from work,family,friends and community mount,many people consider sleep the least expensive
item on his programme.In our society,you're considered dynamic if you say you only need 5.5hours'
sleep.If you'ye got to get 8.5 hours,people think you lack drive and ambition.
To determine the consequences of sleep deficit,researchers have put subjects through a set of psycho-
logical and performance tests requiring them,for instance,to add columns of numbers or recall a passage
read to them only minutes earlier."We'ye found that if you're in sleep deficit,performance suffers,"says
Dr. David."Short-term memory is weakened,as are abilities to make decisions and to concentrate." People in the 18th and 19th centuries used to sleep about 9.5 hours a night because they had_______.
A.no drive and ambition
B.the best sleep habits
C.no electric light
D.nothing to do in the evening