听1段材料，回1-5小题。 1. What makes most students sleep less than nine hours every night? [     ] A. Watching TV. B. Playing computer games. C. Doing their homework. 2. Who else gives children some homework to do except their teachers? [     ] A. Their parents. B. Other students. C. The children themselves. 3. Why does it take some students a lot of time to do their homework? [     ] A. Because they are careful enough. B. Because they are not careful enough. C. Because they watch TV too much. 4. How many hours of sleep is good for students' health? [     ] A. Less than 9 hours. B. Over 9 hours. C. Only 9 hours. 5. What would happen to a student who often goes to bed late and gets up early? [     ] A. He would fall asleep in class. B. He would do well in study. C. He would have good health.