B. Had Visited 13. I........all of my homework last night B. will finish learning English a few years ago A visited C. am visiting D. have visited A. finish C. have finished De finished 14. Lan.. A. starts B. will start Cy started D. is starting 15. By the time I went to bed last night, I... .my homework A. have already finished C. had already finished 16. There..........many significant advances in Vietnamese education recently B. already finished D, were already finishing B. will be C. had been American more than 500 yearsago A. are D. have been 17. Christopher Columbus.... B. has discovered A. discovered C. had discovered D. had been discovering 18. My uncle wishes he.... time when he was young D. didn't waste A. wouldn't waste B. hadn't wasted 19."There is somebody walking behind us. I think we are. . A. followed 20. Jack....... A. didn't play 21. I was tired when you saw me because I..... C. hasn't wasted D. being following B. being followed C. following .chess before, so I showed him what to do B. wasn't playing C. hadn't been played D. hadn't played ..for the exam B have been studying would study A. studied C. had been studying