Tenses and voices A. 现在完成时: 1)表示过去某时发生的行为对主语目前产生的影响。即用过去发生的某个行为来说明现在的某种情况。往往含有“已经……”, “已经……了”的意思。 Eg.Don’t think any more about it. I have decided not to help you. I have experienced that before, so I know how to deal with it.
2)到目前为止已发生的。与so far, up till now, in the past/ last …….days/ years, today, this month/ year 等 “包括现在在内的时间状语”连用。 My brother is an actor. He has appeared in several films so far. Great changes have taken place in this area in the recent years.
3)表示过去开始的动作或状态延续到现在。与for…/ since 连用。 He has worked in the south for ten years/ since ten years ago.
Compare (1):完成进行时表示过去开始的动作一直在进行，直至现在。 He has been working on this project since last month.
(2) 过去时态:指发生在过去某段时间内的事。 He once worked in the south for ten years (现在不在南方)
(3) 过去完成时态:指发生在过去某个时间以前的动作或状态。常与by/ by the end of…(到了……的时候”连用。例如： 1)By the time we got to the theatre, they had sold all the tickets.
2)How many words had you leaned by the end of last year?
B. Practice: 1.It is reported that the president once______ in the Viet Nam’s war for three years from 1966-1970. A. served B. had served C. has served D. was serving 2.—No one answered when I called at 6 yesterday. —I ________ to rock music and was absorbed in it. A listened B was listening C. has listened D. had listened 3.I wasn’t paying attention to what he was talking about, so I am afraid I ___ his speech very well. A. had not understood B. has not understood C. did not understand D. don’t understand 4.I _____ good at table tennis, but I haven’t played it for ages. A. am B. was C. has been D. used to be 5.I _________ where she gets her money all these days. A. am often wondering B. often wondered C. had often wondered D.have often wondered 6.—Tell me what _______ while I was absent. —A thief tried to break into the house when I _______ in your house. A. happened/ stayed B. was happening/ was staying C. happened/ was staying D. was happening/ stayed 7.—You are always watching TV. —Only on Sundays. And nobody ______ it but you. A. knows B. has known C. knew D. is knowing 8.When the old man ______ to walk back to his house ,the sun _____ itself behind the mountain. A.started ;had already hidden B.had started ;had already hidden C.had started ;was hiding D.was starting; hid 9.Years ago we didn’t know this, but recent science ______ that people who don’t sleep well soon get ill. A. showed B. has shown C. will show D. is showing 10.It ______ for weeks before the first cold wave struck the area. A. rained B. was raining C. has rained D. had been raining
Keys: a b c a d / c a a b d