5.现在完成时【现在完成时态中的一句多译】

(1)结构： have/has+动词的过去分词  (过去分词变化规则基本与过去式变化相同，有些特殊变化需单独记忆)

(2)用法：

①表示过去发生的动作对现在造成的影响和结果。有时与just, already, yet, recently, before, ever, never, twice, three times等时间状语连用。如：  I have seen the film already.   我已经看过这部电影了。(现在我知道电影的内容了)

②表示从过去某一时刻开始一直持续到现在的动作或状态。常与“since+时间点”，“for+时间段”，及how long, (ever) since, ever, before, so far, in the last/past few years, up to now, till now等时间状 语连用。如：  We've planted thousands of trees in the past few years.   过去几年我们种了成千上万棵树。  So far there has been no bad news.  到现在为止还没有什么坏消息。

(3)一般过去时与现在完成时的区别  一般过去时只强调在过去发生过某事或关注的是动作发生的时间、地点、方式等。而现在完成时则强调过去的动作对现在的影响，因此，若不强调某事对现在的影响就不用现在完成时。如：

I saw the movie yesterday.  我昨天看了这部电影。(强调电影是昨天看的)  I have already seen the film.   我已经看过这部电影了。(强调到现在为止看过这部电影了)  (4)延续性动词  在现在完成时中，如果有持续的时间状语，要把非延续性动词变为延续性动词。如：  I have had the book for two days.  这本书我已经买了两天了。(用had，而不用bought)  I have been in Tokyo for two weeks.  我已经来东京两周了。(用been in，而不用come to)

现将常见的短暂性动词的转化归纳如下。

1.用相应的延续性动词替换短暂性动词。

buy → have   borrow → keep   put on →wearbecome→becatch a cold→have a cold

come to work→workbegin to teach→teach

get to know→knowmake friends→be friendsfall ill→ be ill

1). buy → have (买)

I bought the bike three weeks ago.

I have had the bike for three weeks.

I have had the bike since three weeks ago.

It is three weeks since I bought the bike.

Three weeks has passed since I bought the bike.

2.用be+形容词或副词替换短暂性动词。

die → be dead       leave→ be away(from)

finish / end→ be over    begin / start → be on

open → be open        close → be closed

come here → be here    come back→ be back

marry → be married

fall asleep / get to sleep → be asleep

return → be backget up→be up

1). die → be dead

He died three years ago.

He has been dead for three years.

He has been dead since three years ago.

It is three years since he died.

Three years has passed since he died.

3.用be+介词短语替换短暂性动词。

join→ be in the+组织/ be a +成员

come / go to Beijing / Dalian→be in Beijing / Dalian

arrive at (in) / reach / get to →be in / at +地点名词

6.过去进行时

(1)结构： was/were+doing

(2)用法：  过去进行时主要表示过去某一时间点或某一段时间正在进行的动作。如：  His father fell down while he was riding  hisbicycle and hurt himself.他爸爸骑自行车时摔倒了，弄伤了自己。

(3)常用的时间状语： this morning, the whole morning, all day yesterday, from nine to ten, last evening, when, while

(4)when和while的区别：

①引导时间状语从句时，while 连接的是时间段，后常接延续性动词;而when连接的既可以是延续性动词也可以是非延续性动词。如：

What was your father doing while your mother was cooking?  你妈妈正在做饭时，你爸爸干什么呢?  What was your mother doing when you came back?  当你回来时，你妈妈干什么呢?  ②while可以连接两个并列的句子，而when不可以。如：  I was trying my best to finish my work while my sister was watching TV.   我当时正在尽力完成作业，而我的妹妹正在看电视。  ③when可作特殊疑问词，对时间进行提问，while 不能。如：  When were you born?你是什么时候出生的?