单项选择题
A.change his energy cycle B.overcome his laziness C.get up earlier than usual D.go to bed earlier
A.Getting off to work with a minimum effort helps save one's energy. B.Dr. Kleitman explains why people reach their peaks at different hours of day. C.Habit helps a person adapt to his own energy cycle. D.Children have energy cycles, too.
A.Nawareness of energy cycles. B.Familiar monologues. C.A change in a family member's energy cycle. D.Attempts to control the energy cycle of other family members.