在英语越来越重要的21世纪，学好英语成了大学生的首要目标。为帮助大学生更好地掌握英语知识，特提供以下文章：
1. Mike, you____play with fire. You____ burn yourself.
A. won't; can't
B. mustn't; may
C. don't have to; must
D. have got to; shouldn't
2. You____see the doctor, Joe. You don't look very well.
A. must
B. shall
C. may
D. can
3. —Must I clean the window now?
—No, you____
A. mustn't
B. needn't
C. can't
D. may not
4. Jack's ill, so they____change their plans.
A. must
B. should
C. have got to
D. ought to
5. Harry has been reading all day —he____be tired.
A. should
B. has got to
C. has to
D. must
答案：
1-5 BABCD