二、单项填空（共15小题，每小题1分，满分15分）
21. ---Are you going to Tim’s birthday party?
---__________. I might have to work.
A. It depends B. Thank you C. Sounds great D. Don’t mention it
22. A survey was carried out on the death rate of those who were infected by smoking, __________were surprising.
A. as results B. which result C. the results of it D. the results of which
23. ---I saw your aunt take a bus to the railway station. Why didn’t you drive her there?
---I __________. But my car __________.
A. would; was fixed B. would have; was fixed
