下列关于地球运动的叙述，正确的是（　）

—It's in my desk.

    “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 up over and over again. That may be the dreamer 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.

    Too much dreaming can be harmful. The more we sleep, the longer we dream. The mind is still at work when we dream. That is why we may have a long sleep and still tired after waking up.