A、A third. B、Almost two thirds. C、More than two thirds. D、Almost half. B题目问的是美国睡眠不足的人群比例是多少。由定位句可知，有63％的美国人每天睡不够8小时，也就是几乎三分之二的人。

"Sleep in America" poll, which looks at the relationship between Americans ’ lifestyles, sleep habits and sleep problems. Sleep deprivation continues to be widespread in America. According to the NSF poll, 63% of American adults do not get the recommended eight hours of sleep needed for good health, safety, and optimum performance. In fact, nearly one third report sleeping less than seven hours each week night, though many adults say they try to sleep more on weekends. This poll shows good news and bad news. The good news is that many Americans say they don’ t want to give up any more sleep in spite of their hectic lives. And they would sleep more if they were convinced it would contribute to their quality of life. The bad news is far too many adults still sacrifice sleep, which is unhealthy and counter productive. Is getting less sleep a trend in developed society? Perhaps some of you callers may be able to shed some further light. Let’ s open up the phone lines at 54 389 282. And we have our first caller now.
    Q22: What proportion of Americans do not get enough sleep?
    Q23: What is the good news about the results of the poll?
    Q24: How will the host spend the remaining part of the show?