Recently Dr. Cleiman has proved that everyone had a daily energy cycle.
During the hours when you labour through your work, you may say that you are "hot". That is 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.
(76) Much family quarrelling ends when husbands and wives realize what this energy cycle means and which cycle each member of the family has.
You cannot change your cycle, but you can learn to make your life fit it better. Dr. Cleiman believes that habits can help. (77) If your energy cycle is low in the morning but you have an important job early in the day, rise before your usual hour, and then you will work better at your low point.
Get up with a lazy yawn (呵欠) and stretch. Sit on the edge of bed before putting your feet on the floor. Avoid the troublesome searching for clean clothes by laying them out the night before.
Dr. Cleiman did not explain in the passage ______.

A. how people can make their life fit their cycle
B. whether everyone has a daily cycle or not
C. why people have their energy cycle of body at different times
D. what will happen in the family if the couple fail to realize which cycle each member has.