听下面一段材料,回答第1-3题.
1. What have scientists discovered in the past 20 years?
A. The strong effect of sleep and dreams.
B. A good night's sleep makes a person less sleepy.
C. Sleep and dreams don't affect the way people feel.
2. Which of the following is true according to the passage?
A. What happens in a dream is more important.
B. The person who appears in a dream is more important.
C. The dream character doesn't affect the person's performance during the day.
3. What wiU make a person happier after sleeping?
A. If he has enough sleep at night.
B. Hhe dreams what he does during the day.
C. If the special character appears in his dreams.