题目

A Insomnia is the inability to fall asleep or sleep restfully. It is a problem to nearly everyone at some time .A person may be awake for an hour in the middle of the night and then , next morning, feel that he hardly sleep all night Normally, worry about not getting enough sleep is the worst aspect of most insomnia. If insomnia is recurrent, however, it is important to find its causes and try to correct them, with the help of a doctor if necessary. Any of a large number of simple factors may take it difficult for someone to fall asleep or remain asleep. His matters may be too soft or too hard“请确定物体在5s时的位置”，这里的“5s时”应理解为（　　）A．0到5s末这一段时间B．4s末到5s末这一段时间C．5s末这一时刻D．5s初，即4s末这一时刻