Dreaming is an activity of the brain. It produces electrical waves which can be measured.  You have dreams when brain waves are 【小题1】fast.

Everyone dreams. If you think that you never dream, you are wrong. Most of the time, we cannot remember our dreams. Some scientists say that we dream mostly about the thoughts and wishes that we try not to show to others. Others say that if dreaming is not strong 【小题2】, it is difficult to remember them anyway.

Most people cannot control their dreams, they just happen. Very few people have clear dreaming. They can control what takes place in their dreaming while they are asleep.

Even blind people dream. They may see pictures of events that have happened to them before they became blind. 【小题3】, a person who was born blind does not see pictures in dreams, but they can hear, smell and taste in them.

People often have the same dreams【小题4】again. They may be events in your life that have caused problems which you have not solved yet. Nightmares are dreams that are so terrible that you usually wake up. There is 【小题5】treatment（治疗）for nightmares. You can go to a doctor who tries to find out why you have nightmares and how to deal with them.