吳明平

【知識總結(jié)歸納】

一、現(xiàn)在完成時的時間狀語

現(xiàn)在完成時的時間狀語（包括副詞、短語、從句等）主要有三種類型，分別用于不同意義的句子之中。

1. 表達(dá)“現(xiàn)在剛剛完成”的動作：

副詞：just, already, yet, recently（lately）, etc.

短語：so far, these+（最近）一段時間，etc.

2. 表達(dá)某種經(jīng)歷或經(jīng)驗

副詞：ever, never, once, twice, before, etc.

常用句：How many times…?

3. 表達(dá)“過去繼續(xù)到現(xiàn)在的動作或狀態(tài)”，常與for和since連用。如：

for two weeks, for a long time since+過去時間點/n./一段時間+ago/一般過去時的從句

在以上的時間狀語中需要認(rèn)真區(qū)別的就是“since+一段時間+ago”這個結(jié)構(gòu)，它與“一段時間+ago”含義不同，前者為時間段，后者為時間點。

二、一般過去時與現(xiàn)在完成時的比較

1. 在表達(dá)“過去的經(jīng)歷、經(jīng)驗”的概念時，如果時間不確定，用現(xiàn)在完成時，如果時間確定，則用一般過去時。如：

Ive met him before.

I met him two days ago.

2. 在when或what time引導(dǎo)的特殊疑問句中，不能用現(xiàn)在完成時。如：

When have you visited New York?

When did you visit New York?

3. 過去發(fā)生的連串動作，如用and, but, or, so等對等連詞連接，要用一般過去時。

三、延續(xù)性動詞與瞬間動詞

例1： Mr. Green ____ for two hours.

A. has gone B. has left

C. has arrived D. has been away

例2： I ____ for six months.

A. have received Johns letter

B. have heard from John

C. havent heard from John

D. havent heard from Johns letter

以上兩題都涉及了延續(xù)性動詞與非延續(xù)性動詞，即瞬間動詞，所謂延續(xù)性動詞，又稱為持續(xù)性動詞，即可以表示持久動作或狀態(tài)的動詞，如drink, eat, read, play, fly, talk等詞，這些動詞有以下特點：

（1）可以和表示時間段的狀語連用

The students have played for an hour.

Mr. Green has read for about four hours.

He will stay there for two weeks.

（2）可以用于進(jìn)行時態(tài)

I am writing an important letter.

It was raining hard when we got off the train.

瞬間動詞，也叫終止性動詞，暫時性動詞或“點動詞”，如open/close, leave, come, go, put, arrive, finish, borrow, lend, marry等動作在極短的瞬間時間內(nèi)完成的，也就是說該動作一發(fā)生即直接轉(zhuǎn)入結(jié)束，結(jié)果狀態(tài)，這類詞有以下特點：

（1）不能和表示一段時間的時間狀語連用，試看以下例句：

① 我感冒一個星期了。

② 五天來我一直穿著那些藍(lán)上衣。

（2）瞬間動詞的否定形式可以表示狀態(tài)，也就可以和“時間段”的狀語連用。如：

Ive not heard from him for a month.

I didnt go to bed until 12 oclock.

（3）瞬間動詞用于進(jìn)行時態(tài)時，一般指重復(fù)動作，而不是指一次動作，如：

He was jumping to keep warm.

He was knocking at the door.

延續(xù)性動詞與瞬間動詞可以在不同的句子結(jié)構(gòu)或不同時態(tài)的句子之間進(jìn)行相互轉(zhuǎn)換，表達(dá)相同的意思。如：電影已經(jīng)放映十分鐘了。

The film began ten mimutes ago.The film has been on for ten minutes.

這兩種動詞的相互轉(zhuǎn)換有三種形式：

1. 將瞬間動詞轉(zhuǎn)換成為延續(xù)性動詞，并與表示時間段的狀語連用。

He bought the book two weeks ago. He has had the book for two weeks.

His brother has been in the army for 3 months. His brother joined the army 3 months.

常用的這類轉(zhuǎn)換有l(wèi)end/borrow→keep buy→have，join→be in，marry→be married，open/close→be open/closed， die→be dead等。試完成這個句子轉(zhuǎn)換：

John borrowed the book three days ago.

John ____ the book ____ three days.

2. 用“It is+時間段+since”句型進(jìn)行轉(zhuǎn)換。如：

He has studied in our school for four years.

It is four years since he came to study in our school.

在這類轉(zhuǎn)換中，since所引導(dǎo)的從句為一般過去時，且謂語動詞多為瞬間動詞。試完成這個句子的轉(zhuǎn)換：

Her mother died two years ago.

It is ____ since ____.

3. 用“時間段+has passed+since”句型進(jìn)行轉(zhuǎn)換，如：

I have been in the army for two years.

Two years has passed since I joined the army.

由此可見，剛才的句子“電影放映十分鐘了”，還可以用上述的2、3句型來表達(dá)。即：

It is ten minutes since the film began.

和Ten minutes has passed since the film began.