单项选择题
A special lab at the University of Chicago is busy only【C1】______.It is a dream【C2】______where researchers are at work【C3】______dreamers.Their findings have concluded that【C4】______dreams from three to seven times each night,【C5】______in ordinary life a person may【C6】______none or only one of his dreams.
While the【C7】______sleep,special machines【C8】______their brain waves and eye movements as well as the body movements that【C9】______the end of a dream.Surprisingly,all subjects【C10】______soundly.
【C11】______say that a person usually fidgets before a dream.【C12】______the dream has started,his body relaxes and his eyes【C13】______more active,as if the curtain【C14】______on a show.When the machine【C15】______that the dream is over,a buzzer wakes the【C16】______He sits up,records his dream,and goes back to sleep perhaps to【C17】______some more.
Researchers have found that if the dreamer,is【C18】______immediately after his dream,he can usually recall the entire dream,If he is allowed to sleep even【C19】______his【C20】______of the dream will have faded.
A.at noon
B.in the morning
C.at night
D.in spring