Dream is story that a person " watches" or even takes part in during sleep. Dream events ar imaginary, but they are related to real experiences and needs in the dreamer's life. They seem real whil they are taking place. Some dreams are pleasant, others are annoying and still others are frightening. Everyone dreams, but some persons never recall dreaming. Others remember only little abouta dream they had just before awakening and nothing about earlier dreams No one recalls all his dreams. Dreams involve little logical thought。 In most dreams, the dreamer cannot control what happens to him. The story may be confusing, and things happen that would not happen in real life. People see in see in most dreams, but they may also hear, smell, touch, and taste in their dreams. Most dreams occur in color, but persons who have been blind since birth do not see at all in dreams. Dreams are product of the sleeper's mind. They include events and feelings that he has experienced. Most dreams are related to events of the day before the dream and strong wishes of the dreamer. Many minor incidents of the hours before sleep appear in dreams. Few events more than two days old tumn up. Deep wishes or fears-especially those held since childhood-often appear in dreams, and many dreams fulfill such wishes. Events in the sleeper's surrounding-a loud noise, for example may become part of a dream, but they do not cause dreams. Some dreams involve deep feelings that person may not realize he has. Psychiatrists(精神病医生 often use material from a patient's dreams to help the person understand himself better. Dreaming may help maintain good learning ability, memory, and emotional adjustment. People who get plenty of sleep-but are awakened each time they begin to dream-become anxious and restless.