题目内容：
阅读下列文章，选出题的最佳答案：A special lab at the University of Chicago is busy only_41_ It is a dream_42_ where researchers ale at work _43_dreamers．Their findings have concluded that_44_dreams from three to seven times each night，_45_in ordinary life a person may_46_none or only one of his dreams．
While the_47_sleep，special machines_48_ their brain waves and eye movements as well as the body movements that _49_the end of a dream．Surprisingly，all subjects_50_ soundly．
_51_ say that a person usually fidgets(烦躁)before a dream．_52_ the dream has started．his body relaxes and his eyes_53_ more active，as if the curtain_54_on a show．When the machine_55_ that the dream is over，a buzzer wakes the _56_．He sits up，records his dream, and goes back to sleep--perhaps to_57_ some more．
Researchers have found that if the dreamer，is_58_ immediately after his dream．he can usual1y recall the entire dream．If he is allowed to sleep even_59_his_60_of the dream will have faded That’s why most people have many dreams at night，but forget most of them in the morning．
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