Ⅰ.单句语法填空
1．She hesitated(hesitate)before picking up the phone because she didn't know how to refuse the invitation.
2．If you want to have an examination，please make an appointment(appoint)with my secretary.
3．The government is committed to improving (improve) social security and health care.
4．Their suggestions have no scientific basis(base)．
5．Scientists have many theories about how the universe first came into existence(exist)．
6．Operation(operate) of this equipment requires special training.
7．I would be surprised if he turned up unexpectedly.
8．Can you give me some advice on how to make up for the time I have lost?
9．Judging(judge)from his dress，he is probably a Tibetan.
10．She made no response(respond) to my letter.
