问题
单项选择题
Why does a lack of sleep cause people to gain weight().
A.Because people burn fewer calories when they are awake.
B.Because people feel hungry when they lack sleep.
C.Because their hormones stay unchanged.
D.Because people don’t exercise when they don’t have enough sleep.
答案
参考答案：B
解析：
[分析]： 原因结果。 题干：为什么缺乏睡眠会导致人们变胖根据原文“Researchers say a lack of sleep can produce hormonal changes that increase feelings of hunger．”，译文为：研究人员说缺乏睡眠会导致荷尔蒙的变化，这种变化会增强饥饿感。所以选c“因为人们缺乏睡眠时会感到饥饿。”。a选项为“因为在清醒的时候燃烧的卡路里较少。”，c选项为“因为他们的荷尔蒙没有改变。”，d选项为“因为人们睡眠不足时不运动。”