Sleeping
1 For millions of years before the appearance of the electric light, shit work, all night cableTV and the Internet, earth's creatures evolved (进化) on a planet with a 24-hour cycle. Our biological clocks are set for this daily cycle. Simply, our bodies want to sleep at night and beawake during the day. Most women and men need between 8-8.5 hours of sleep a night to function properly throughout their lives.
2 But on average, Americans sleep only about seven and a half hour per night, a marked drop from the nine hours they averaged in 1910. What's worse, nearly one third of all Americans get less than six hours of sleep on a typical work night. For most people, that's not nearly enough.
3 Finding ways to get more and better sleep can be a challenge. Scientists have identified more than 80 different sleep disorders( 紊乱). Some sleeping disorders are genetic. But many problems are caused by staying up late and by traveling often between time zone or by working nights, Dr. James F. Jones at National Jewish Medical and Research Center in Denver says that sleepdisorders are often diagnosed (诊断) as other discomforts. About one third of the patients referred to him with possible chronic fatigue syndrome (慢性疲劳综合征) actually have treatable sleep disorders. "Before we do anything else, we look at their sleep," Jones says.
4 Sleep experts say that most people would benefit from a good look at their sleep patterns. "My motto （座右铭) is ‘Sleep defensively'," says Mary Carskadon of Brown University. She says people need to find sufficient time to sleep, even if it means giving up other things. Going to bed and getting up at the same time every day are important.
5 Pre-bedtime activities also make a difference. As with Eisner, who used to suffer from sleeplessness, a few life style changes---avoiding stimulants (刺激) and late meals, exercising hours before bedtime, relaxing with a hot bath-cause better sleep.
前5道题选项：
A. Sleeping patterns
B. Sleeping cycle
C. Sleeping disorders
D. Sleeping time
E. Sleeping habit
F. Sleeping activities
后5道题选项：
A. eating and drinking more
B. having enough sleep
C. sleeping for 8-8.5 hours
D. taking a hot bath
E. giving up other things
F. staying up late
Mary said we should have enough time to sleep by ______________.
E