A unique laboratory at the University of Chicago is busy only at night. It i

A unique laboratory at the University of Chicago is busy only at night. It is a dream laboratory where researchers are at work studying dreamers. Their findings have(26)revealed that everyone dreams from three to seven times a night; although(27)in ordinary life a person may remember none or only one of his dreams. What people dream usually(28)reflects their waking life experiences, which are mostly visual in nature. Dream is(29)considered to be a passive event, a(30)phenomenon that people experience but do not(31)consciously control. While the subjects — usually students — sleep, special machines record their(32)brain waves and eye movements as well as the body movements that signal the end of a dream. Surprisingly, all subjects sleep(33)soundly. Observers report that a person usually feels anxious before a dream. Once the dream has started, his body relaxes and his eyes become more active, as if the curtain had gone up on a show. As soon as the machine indicates that the dream is over, the sleeper is weakened by the researcher. He(34)sits up, records his dream, and goes back to sleep — perhaps to dream some more. Researchers have found that if the dreamer is wakened after his dream(35)without delay, he can usually recall the entire dream. If he is allowed to sleep even five more minutes, his memory of the dream will have faded.