根据要求完成下列句子：
1. You must hand in your exercise book at once. （改成一般疑问句）
2. He must be joking.（改成否定句）
3. She must be hungry now, _______? （完成反意疑问句）
4. They must have arrived in
5. He must have known the news, ________? （完成反意疑问句）
6. He has to reach there in an hour.（改成一般疑问句）
7. She had to tell me the truth, ________? （完成反意疑问句）
8. He doesn’t have to work too hard, ________? （完成反意疑问句）
参考答案:1. Must you hand in your exercise book at once?
2. He can't be joking.
3. isn't she
4. didn't they
5. hasn't he
6. Does he have to reach there in an hour?
7. didn't she
8. does he
