阅读理解。 'Dreams may be more important than sleep. We all need to dream,' some scientists say. Dreams take up about one quarter of our sleeping time. People have several dreams each night. Dreams are like short films. They are usually in color. Some dreams are like old films. They come to us over and over again. That may be because the dreamer is worrying about something. Dreaming may be a way of trying to find an answer. Some people get new ideas about their work from dreams. They may have been thinking about their work all day. These thoughts can carry over into dreams. Sometimes we wake up with a good feeling from a dream. But often we can't remember the dream. Dreams can disappear (消失) quickly from memory. Too much dreaming can be harmful (有害的). The more we sleep, the longer we dream. The mind is hard at work when we dream. That is why we may have a long sleep and still wake up tired. 1. It may be less important to sleep than to ______. 2. Dreams and films are usually ______. 3. Some people often dream about their work because ______. 4. If we sleep too long, we will feel ______. 5. It is ______ for our health if we have too many dreams at night.