[单项选择]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 labor through your work 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 (独白) as: "Get up, John! You’’ll 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 quarreling 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 be
A. he is a lazy person
B. he is not sure why his energy is low
C. he refuses to follow his own energy cycle
D. he is at his peak in the afternoon or evening

[单项选择]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 labor 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 before noon. For others it comes in the afternoon or evening. No one has discovered why this is so, but it leads to such familiar saying as: "Get up, John! You’re 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 end 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. If your energy
A. Getting off to work with a minimum effort helps save one’ s energy.
B. Dr. Kleitman explains why people reach their peak at different hours of day.
C. Habit helps one adapt to his own energy cycle.
D. Children have energy cycles, too.