[单项选择]

Chronic insomnia is a major public health problem. And too many people are using (1) therapies, even while there are a few treatments that do work. Millions of Americans (2) awake at night counting sheep or have a stiff drink or (3) an pill, hoping it will make them sleepy. (4) experts agree all that self-medicating is a bad idea, and the causes of chronic insomnia remain (5) .a

Chronic insomnia is a major public health problem. And too many people are using (1) therapies, even while there are a few treatments that do work. Millions of Americans (2) awake at night counting sheep or have a stiff drink or (3) an pill, hoping it will make them sleepy. (4) experts agree all that self-medicating is a bad idea, and the causes of chronic insomnia remain (5) .
Almost a third of adults have trouble sleeping, and about 10 percent have (6) of daytime impairment that signal tru
A. cause
B. accompany
C. follow
D. attend

Chronic insomnia is a major public health problem. And too many people are using (1) therapies, even while there are a few treatments that do work. Millions of Americans (2) awake at night counting sheep or have a stiff drink or (3) an pill, hoping it will make them sleepy. (4) experts agree all that self-medicating is a bad idea, and the causes of chronic insomnia remain (5) .
Almost a third of adults have trouble sleeping, and about 10 percent have (6) of daytime impairment that signal true insomnia. But (7) the complaints, scientists know surprisingly little about what causes chronic insomnia, its health consequences and how best to treat it, a panel of specialists (8) together by the National Institutes of Health concluded Wednesday. The panel called (9) a broad range of research into insomnia, (10) that if scientists understood its (11) causes, they could develop better
A. unproven
B. unknown
C. improper
D. imperative