二、单项选择(共15小题,15分。每小题1分)
       从各题A、B、C、D四个选项中,选出可以填入空白处的最佳答案。
21. ––Listen! Someone is knocking at the door. Is it Emily?
  ––It ______ be Emily. She has gone to Guangzhou.
A. must                    B. can’t                           C. needn’t                      D. may 
22. In many places in China, ______ bicycle is still ______ popular means of transportation.
A. the; 不填                B. 不填; a                     C. the; a                D. 不填; 不填
23. Anne asked John ______ he would like a part-time teaching job.
       A. whether                    B. who                            C. that                          D. what 
24. ––Can David take charge of the international department?
     ––I’m afraid it’s ______ his ability. 
     A. under                     B. within               C. over                     D. beyond
25. My toothache ______ me. I thought it was going away but it’s getting worse and worse.
A. is killing              B. kills                              C