1) since +过去一个时间点(如具体的年、月、日期、钟点、1980, last month, half past six)。
I have been here since 1989.
2) since +一段时间+ ago
I have been here since five months ago.
3) since +从句
Great changes have taken place since you left.
Considerable time has elapsed since we have been here.
4) It is +一段时间+ since从句
It is two years since I became a postgraduate student. 1) 用于完成时的区别
延续动词表示经验、经历； 瞬间动词表示行为的结 果，不能与表示段的时间状语连用。
He has completed the work.他已完成了那项工作。 (表结果)
I've known him since then. 我从那时起就认识他了。(表经历)
2)用于till / until从句的差异
作为延续动词一般用于肯定句，表示"做……直到……" 作为瞬间动词一般用于否定句，表示"到……，才……"
He didn't come back until ten o'clock.
他到10 点才回来。
He slept tll ten o'clock.
他一直睡到10点。 1. You don't need to describe her. I ___ her several times.
A. had met B. have met C. met D. meet
答案B. 首先本题后句强调对现在的影响，我知道她的模样，你不用描述。再次，several times告知为反复发生的动作，因此用现在完成时。
2.---I'm sorry to keep you waiting.
---Oh, not at all. I ___ here only a few minutes.
A. have been B. had been C. was D. will be
答案A. 等待的动作由过去开始，持续到现在，应用现在完成时。 1．写出下列单词的过去式、过去分词
arrive _________ _________
brush _________ __________
send _________ _________
write _________ __________
hear _________ __________
fall _________ __________
drop_________ __________
lose _________ __________
feel _________ __________
lose__________ __________
use _________ __________
wear _________ _________
think________ __________
thank_________ _________
own _________ __________
invent ________ _________
build _________ _________
allow _________ __________
2. 用单词的适当形式填空
1).- _____ you ______(write )your letter yet ? – Yes, I _______ (write ) it last night .
2)- Jim ____________ ( not finish ) his homework yet .When _______ he ________(finish ) it? - Maybe tomorrow .
3) -I ________ never _______ (be) to America before . What about you ? -I _________ (go) there last year .
4) –Where is your father ? -He _______ (go ) to Beijing . He ________ (leave ) five days ago . 5)-I’m sorry to keep you waiting here.
-Oh, it doesn’t matter . I ________ (be) here for only a few minutes . 6) We will wait here until another bus _______ (come ) .
7) –Have you finished your homework ,Tom ? – Not yet . I _________ (do) it now . 8)- When ______ you ______ (plant ) the tree ? – Last year.
9) I don’t know if Mary ________ (come) .If she _______ (come), I’ll tell her what to do . 10)- _____ you _____ (go) and ______ (see) a film with me tonight ? -No, I won’t . I _______ (see) it already .
11) We ______ (hold) a meeting yesterday . And there ________ (be) another one tomorrow . 12)- Who _____ (win ) the men’s football match ? – We did .
13) The students of Grade Three ________ (learn) more than 2000 English words so far . 14)- How long _____ your grandfather _____ (be ) dead ? – For two years . He ______ (die ) the year before last .
15)- _____ you _____ (read ) this book before ? –Yes ,I ______ (read ) twice . 16) It ______ (be) five days since he ______ (leave ) his hometown . 17) I ______ (wait )you for a long time . Where _____you _____ ( be) ?
18) All the children _______ (enjoy )themselves now .Some ______ (sing ) , some ______ (dance ), others _______ (play ) games .
19) China _______ (send ) many man-made satellites into the space in the last three years . 20) When I ______ (leave ) school a moment ago ,it ________ (rain ) hard . 21) Don’t watch TV until your homework ________ (do) . 22) He ________just ______ (travel) to foreign countries .
23) We _________ ( not see) each other since we ________ ( leave ) middle school.
24) While I _______ (walk) on the road last night , I ______ (meet) an old friend of mine . 25)- ______ your mother ever______ (watch) such a film ? – No, never.
3.转变句型
1） He joined the army two years ago . He ______ ______ ______ the army _____ two years . 2） The man bought a new car last month . The man ______ ______ a new car ______ last month . 3） The baby fell asleep five minutes ago . The baby _______ ______ asleep _____ five minutes . 4） They opened the shop last week . The shop ______ ______ _______ for a week .
5） Tom borrowed the books yesterday . Tom ______ ______ the books for only one day . 6） The film began half an hour ago . The film ______ _______ ______ for half an hour .
7） She became a League member last year . She _____ ______ a League member _____ last year. 8） The girl left her hometown ten years ago .
The girl _____ _____ ____ _____her hometown for ten years . 9） I got to know him three years ago . I_____ _____ him ______ three years . 10） We began to learn English two years ago . We ____ ____ English ____ two years ago
