有些人甚至晚上睡觉前就能决定第二天早晨几点起床，结果他们也恰恰在预定时间前后的一两分钟内醒来，就好像人体内有一个生物钟，它自动运转，从不需要上发条。

• And some persons can even decide before they go to sleep at night just what time they are going to wake up the following morning. Then they wake within a minute or two of that time. It's as though the body has an inner clock. His inner clock runs automatically,and it never needs winding.