6. Jane can’t attend the meeting at 3 o’clock this afternoon because she ______ a class at that time.     

  A. will teach                                                         B. would teach             

C. has taught                                                       D. will be teaching

7. I ______ have worried before I came to the new school, for my classmates here are very friendly to me.

A. mightn’t                  B. mustn’t                       C. needn’t                       D. couldn’t

8. ______ for two days, Steve managed to finish his report on schedule.

  A. To work                                                             B. Worked                      

C. To be working                                                D. Having worked

9. Despite the previous rounds of talks, no agreement______ so far by the two sides.

A. has been reached                                         B. was reached

C. will reach                                                         D. will have reached

10. Tom had to______ the invitation to the party last weekend because he was too busy.

  A. turn in                                                               B. turn down                 

C. turn over                                                          D. turn to

11. If you have any doubts about your health, you’d better______ your doctor at once.

  A. convince                B. consult                        C. avoid                           D. affect

12. We need to get to the root of the problem______ we can solve it.

  A. while                       B. after                            C. before                                 D. as

13. I wish I ______ at my sister’s wedding last Tuesday, but I w