聽下面一段獨(dú)白，回答小題。
（1）What can cause problems in a student's study？
A.Fighting with parents.
B.Getting up late.
C.Falling asleep in class.
（2）Who suggests that students should have 9 hours' sleep every night？
A.Parents.
B.Scientists.
C.Teachers
（3）Why do most students feel nervous and forgetful？
A.Because they worry about their studies.
B.Because they don't get enough sleep.
C.Because they often get lower grades.
（4）When should students go to sleep？
A.Before 11 p.m.
B.After 12 a.m.
C.At about 9 p.m.
（5）Most students go to bed late because

.
A.there may be too much noise in their bedrooms.
B.there may be a parent in their bedrooms.
C.there may be a computer in their bedrooms.