21. I’ll go with you as soon as I____my homework.
A.will finish B.finish C.am finishing D.finished
22. All the tissues before the experiment began.
A. have been tested B. had been tested C. were tested D. will have been tested
23.By the end of this month, we surely _____ a satisfactory solution to the problem.
A. have found B. will be finding
C. shall have found D. are finding
24.He was unhappy when he sold his guitar. After all, he _____ it for a very long time.
A. has had B. had had C. has D. had
25. —Nancy is not coming tonight. —But she _______!
A. promises B. promised
C. will promise D. had promised