21. She _______ working on that manuscript for 2 years now. a. will be b. has been c. had been d. is 22. I _______ there once a long time ago and _______ back since. a. went / have not been b. go / am not c. have gone / was d. was going / had not been 23. She _______ trying to pass her driving test but fails every time. a. kept b. is keeping c. had kept d. keeps 24. I _______ complete silence now while I try this experiment. a. am wanting b. want c. did want d. have wanted 25. The students _______ by Mrs. Monty. However, this week they _______ by Mr. Tanzer. a. are usually taught / are being taught b. usually teach / are teaching c. have usually been taught / have been teaching d. were usually teaching / are teaching 26. In the past the trip _______ very rough and often dangerous, but things _______ a great deal in the last hundred and fifty years. a. was / have changed b. is / change c. had been / will change d. has been / changed 27. Now you _______ from New York to Los Angeles in a matter of hours. a. are flying b. would fly c. will fly d. can fly 28. When Carol _______ last night, I ______ my favorite show on television. a. was calling / watched b. called / have watched c. called / was watching d. had called / watched 29. By this time next summer, you _______ your studies. a. completes b. will complete c. are completing d. will have completed 30. Right now, Jim _______ the newspaper and Kathy _______ dinner. a. reads / has cooked b. is reading / is cooking c. has read / was cooking d. read / will be cooking 31. Last night at this time, they _______ the same thing. She _______ and he………. t