由“have/has+過去分詞”構成，主要有兩個含義： ①表示動作發生在過去，但與現在的情況有聯繫，有時無時間狀語，有時和一些表示不確定的過去時間狀語連用，如：many times，just，yet，ever，never，already，before，so far, by now等連用。 ②表示從過去某一時間開始一直延續到現在並還可能繼續延續下去的動作，用於延續性動詞，且句中常帶有表示一段時間的時間狀語，如：for two months, so far等。
基本介紹
- 中文名：現在完成時態
- 類型：英語語法
- 學科：英語
- 特徵：for two months
時態結構,比較過去時與現在完成時,用於現在完成時的句型,典型例題,since用法,延續動詞與瞬間動詞,典型例題,練習題2,
時態結構
①表示動作發生在過去，對現在有影響，有時無時間狀語，有時和一些表示不確定的過去時間狀語連用，如：many times，just，yet，ever，never，already，before，so far, by now等連用。
②表示從過去某一時間開始一直延續到現在並還可能繼續延續下去的動作，用於延續性動詞，且句中常帶有表示一段時間的時間狀語，如：since + 時間點/從句，for two months, so far等。
比較過去時與現在完成時
1）過去時表示過去某時發生的動作或單純敘述過去的事情，強調動作；現在完成時為過去發生的，強調過去的事情對現在的影響，強調的是result (結果）。
yesterday, last week，…ago, in1980, just now, 具體的時間狀語
共同的時間狀語:
this morning, tonight, this April, now, once，before, already, recently，lately
for, since, so far, ever, never, just, yet, till / until, up to now, in past years, always,
不確定的時間狀語
3）現在完成時可表示持續到現在的動作或狀態，動詞一般是延續性，如live, teach, learn, work, study, know.
過去時常用的非持續性動詞有come, go, leave, start, die, finish, become, get married等。
舉例：
I saw this film yesterday.
（強調看的動作發生過了。）
I have seen this film.
（強調對現在的影響，電影的內容已經知道了。）
Why did you get up so early?
（強調起床的動作已發生過了。）
Who hasn't handed in his paper?
（強調有卷子，可能為不公平競爭。）
She has returned from Paris.
她已從巴黎回來了。
She returned yesterday.
她是昨天回來了。
He has been in the League for three years.
(在團內的狀態可延續)
He has been a League member for three years.
(是團員的狀態可持續)
He joined the League three years ago.
( 三年前入團，joined為短暫行為。)
I have finished my homework now.
---Will somebody go and get Dr. White?
---He's already been sent for.
（錯）Tom has written a letter to his parents last night.
（對）Tom wrote a letter to his parents last night.
用於現在完成時的句型
It is the first time that I have visited the city.
It was the third time that the boy had been late.
2）This is the… that…結構，that從句要用現在完成時.
This is the best film that I've (ever) seen.
這是我看過的最好的電影。
This is the first time (that) I've heard him sing.這是我第一次聽他唱歌。
典型例題
---No, this is the first time I ___ here.
- was B. have been C. came D. am coming
---No, it's the first time I ___ here.
- even, come B. even, have come C. ever, come D. ever, have come
答案D. ever意為曾經或無論何時，反意詞為never，此兩詞常用於完成時。 This is the largest fish I have ever seen. It is / was the first time +that-clause 的句型中，從句要用完成時。
（錯）I have received his letter for a month.
（對）I haven't received his letter for almost a month.
比較since和for
Since 用來說明動作起始時間，for用來說明動作延續時間長度。
I have lived here for more than twenty years.
I have lived here since I was born..
My aunt has worked in a clinic since 1949.
Some new oilfields have been opened up since 1976.
I have known Xiao Li since she was a little girl.
My brother has been in the Youth League for two years.
I have not heard from my uncle for a long time.
I worked here for more than twenty years.
(我現在已不在這裡工作。)
I have worked here for many years.
(現在我仍在這裡工作。)
小竅門：當現在完成時+一段時間，這一結構中，我們用下面的公式轉化，很容易就能排除非延續動詞在完成時中的誤使。
- (對) Tom has studied Russian for three years.
= Tom began to study Russian three years ago, and is still studying it now.
- (錯) Harry has got married for six years.
= Harry began to get married six years ago, and is still getting married now.
顯然，第二句不對，它應改為 Harry got married six years ago.或 Harry has been married for six years.
since用法
1) since +過去一個時間點(如具體的年、月、日期、鐘點、1980, last month, half past six)。
I have been here since 1989.
2) since +一段時間+ ago
I have been here since five months ago.
3) since +從句
Great changes have taken place since you left.
Considerable time has elapsed since we have been here.
4) It is +一段時間+ since從句
It is two years since I became a postgraduate student.
延續動詞與瞬間動詞
1) 用於完成時的區別
He has completed the work.他已完成了那項工作。 (表結果)
I've known him since then. 我從那時起就認識他了。(表經歷)
2)用於till / until從句的差異
作為延續動詞一般用於肯定句，表示"做……直到……" 作為瞬間動詞一般用於否定句，表示"到……，才……"
He didn't come back until ten o'clock.
他到10 點才回來。
He slept tll ten o'clock.
他一直睡到10點。
典型例題
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. 首先本題後句強調對現在的影響，我知道她的模樣，你不用描述。再次，several times告知為反覆發生的動作，因此用現在完成時。
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. 等待的動作由過去開始，持續到現在，套用現在完成時。
練習題2
1．寫出下列單詞的過去式、過去分詞
arrive _________ _________
brush _________ __________
send _________ _________
write _________ __________
hear _________ __________
fall _________ __________
drop_________ __________
lose _________ __________
feel _________ __________
lose__________ __________
use _________ __________
wear _________ _________
think________ __________
thank_________ _________
own _________ __________
invent ________ _________
build _________ _________
allow _________ __________
2. 用單詞的適當形式填空
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.轉變句型
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
