单选题 Do you find getting up in the morning so difficult that it's painful? This might be called laziness, but Dr. Kleitman has a new explanation. He has proved that everyone has a daily energy cycle.
During the hours when you labour through your work you may say that you' re "hot". That' s true. The time of day when you feel most energetic is when your cycle of body temperature is at its peak. For some people the peak comes during the forenoon. For others it comes in the afternoon or evening. No one has discovered why this is so, but it leads to such familiar monologues as, "Get up, John] Yon' 11 be late for work again!" The possible explanation to the trouble is that John is at his temperature-and-energy peak in the evening. Much family quarrelling ends when husbands and wives realize what these energy cycles mean, and which cycle each member of the family has.
You can' t change your energy cycle, but you can learn to make your life fit it better. Habit can help, Dr. Kleitman believes. Maybe you're sleepy in the evening but feel you must stay up late anyway. Counteract your cycle to some extent by habitually staying up later than you want to. If your energy is low in the morning but you have an important job to do early in the day, rise before your usual hour. This won' t change your cycle, but you' 11 get upstream and work better at your low point.
Get off to a slow start which saves your energy. Get up with a leisurely yawn and stretch. Sit on the edge of the bed a minute before putting your feet on the floor. Avoid the troublesome search for clean clothes by laying them out the night before. Whenever possible, do routine work in the afternoon and save tasks requiring more energy or concentration for your sharper hours.

单选题 If a person finds getting up early a problem, most probably______.
【正确答案】 A
【答案解析】根据“daily energy cycle”理论，早起成问题，说明此人在早晨精力状态最差，反过来说明了在下午或者晚上会达到精力的峰值。
单选题 Which of the following may lead to family quarrels according to the passage?
【正确答案】 A
【答案解析】本题参见第二段最后一句：“Much family quarrelling ends when...realize what these energy cycles mean”，只有理解了是怎么回事时，家庭争吵才会结束；反过来家庭争吵是因为对energy cycle的不了解。
单选题 If one wants to work more efficiently at his low point in the morning he should ______.
【正确答案】 A
【答案解析】可以参见第三段，“rise before your usual hour”就是“get up earlier than usual”的另一种表达。
单选题 You are advised to rise with a yawn and stretch because it will_______.
【正确答案】 B
【答案解析】见第四段，“rise with a yawn and stretch”就是“get off to a low a start”的一种，它的目的是为了“save your energy”，也就是“keep your energy for the day's work”。
单选题 Which of the following statements is NOT true?
【正确答案】 D
【答案解析】逐一判断。A选项从首段最后一句“everyone has a daily energy cycle”知道它是对的；B选项是第三段“Habit can help”的引申； C选项参见第四段首句，对于D选项，实际上Dr Kleitman只是证明了每个人都有“energy cycle”，并没有解释为什么不同人会有不同时间的峰值，D选项有误，所以选D。