It seems parents have long been right. Going to bed early is key to getting enough sleep and helping adolescents feel on top of the world, a new study reported.
A   1  of sleep among youngsters may    2  depression and suicidal (自杀的)thoughts, according to the study by the Columbia University Medical Center.
"Our results are   3  with the theory that inadequate sleep is a risk factor for depression, working with other   4  and protective factors through multiple possible causal pathways to the development of this   5  disorder," said lead author James Gangwisch.
"  6  quality sleep could therefore be a preventative measure against   7  and a treatment for depression," he added in the study   8  in the Friday issue of Sleep magazine.
The study followed the nightly habits of some 15,659 college and high-school students, and   9  those who consistently went to bed   10  midnight had a 24 percent higher risk of depression than those who turned in before 10:00 pm.
Night owls（夜猫子）also ran a 20 percent   11  risk of battling suicidal thoughts, the study added.
The American Academy of Sleep Medicine   12  that adolescents should sleep at least nine hours or more a night. Those who were tucked in before 10:00 pm reported they slept    13  about eight hours and 10 minutes.
But that amount of sleep  14  significantly for those in bed after midnight.
And adolescents who slept five hours or less a night were 71 percent more   15  to suffer depression and 48 percent more     16  becoming suicidal, the study said.
"It is a common perception and societal   17  that adolescents do not need as much sleep as pre-adolescents, yet studies suggest that adolescents may  18  require more sleep," said Gangwisch.
"Studies have found that adolescents do not go to bed   19  enough to make up for earlier school start times, and transitions to earlier school start times have been shown to be   20  with significant sleep deprivation（剥夺）. "
(    ) 1. A. night                B. moderation       C. limit                D. lack
(    ) 2. A. result in           B. lie in                C. come about       D. bring in
(    ) 3. A. opposed           B. mixed              C. related              D. consistent
(    ) 4. A. risk                  B. chance              C. potential           D. reason
(    ) 5. A. mood                      B. body                C. feeling             D. mind
(    ) 6. A. little                B. lack                 C. Adequate          D. over
(    ) 7. A. suffering          B. depression               C. disorder            D. sadness
(    ) 8. A. reported           B. published          C. reflected           D. noted
(    ) 9. A. found                      B. investigated      C. appraised          D. supported
(    ) 10. A. before            B. from                C. by                    D. after
(    ) 11. A. lower             B. higher              C. more                D. less
(    ) 12. A. appeals           B. recommends     C. calls                 D. plans
(    ) 13. A. on average      B. in place            C. ahead of           D. in number
(    ) 14. A. increased               B. disappeared       C. strengthened     D. dropped
(    ) 15. A. likely             B. probable           C. possible            D. perhaps
(    ) 16. A. at sight of       B. at risk of          C. in front of               D. as a result of
(    ) 17. A. wish               B. expectation       C. suggestion               D. attempt
(   ) 18. A. exactly           B. immediately      C. directly            D. actually
(    ) 19. A. early              B. lately                      C. soon                 D. quickly
(    ) 20. A. separated               B. associated         C. divided             D. depended