时态复习

一般现在时

a) 代替将来时，用于时间和条件状语从句中。
Please wait till Jane arrives . 请等到简回来。
b) 表预先安排好的动作，常用于 begin , close , depart , finish , open , stop 等动词。
The concert begins at 7:30 and ends at 9:30. 音乐会定于 7 时 30 分开始， 9 时 30 分结束。
现在进行时

有些动词（如go , come , stay , leave , start等）的现在进行时形式也可以表示将来即将发生的动作。
The plane is leaving for London .这架飞机要飞往伦敦。
现在完成时
1．用来表示过去开始，但持续到现在的动作。常和already , before , in the past few months , over the past 5 years, just , so far , up to now ,yet等状语连用。

2．表示过去发生的动作，但对现在仍留下某种后果和影响。

He can't go on holiday because He has broken his leg.

3．在It is the first time + that –分句结构。

It's the third time I have explained this particular aspect of grammar.

4.在时间从句和条件从句中，现在完成时可以代替将来完成时，表示将来某时业已完成的动作。例如：
①You'll get to like the subject after you have studied it for some time.
在学习这个学科一段时间之后，你就会喜欢它的。
②I'll go and see the exhibition as soon as I have finished my work.

我一做完作业就去看展览。

现在完成进行时*
现在完成进行时用来表示从过去某一时间开始一直延续到现在的动作，这个动作可能要继续进行下去。

The children have been watching TV all morning.

一般过去时

1.用来表示过去发生的动作（如yesterday , last week , three years ago , in 1998等）

He made the statement at a meeting with Ambassador Last Friday.

2.一般过去时与现在完成时的区别：
a)现在完成时强调动作现在的结果；过去时着眼过去的动作或状态。
He went to Africa .他到非洲去了。
He has gone to Africa .他已经到非洲去了。
He has been to Africa .他去过非洲。
b)表示过去的时间状语只用于过去时，不能用于现在完成时：
He died ten days ago .
He has been dead for ten days .

过去进行时

表示过去某一时刻或某段时间内正在进行的动作。

I was practicing my oral English at eight o'clock yesterday evening.

When I saw her, she was working at the computer.

过去完成时
用来表示过去某个时间或某个动作之前已经完成的动作，强调过去的过去。

I waited until he had finished his work.

1.过去完成时通常与由介词“by +表示过去时间的名词”构成的短语连用。

By the end of last week we had already done half of the work.

By the time I left the school I had taught that class for ten years.

2.过去完成时通常用在动词said, told, asked, explained, thought, wondered等引起的宾语从句中。

I told them that I had done enough work for one day.

She wondered who had left the door open.

3.在no sooner … than, hardly … when, scarcely … when, barely … when句型中，主句中的谓语动词通常要用过去完成时，从句中谓语动词要用一般过去时。

Hardly had he begun to speak when the audience interrupted him.

过去完成进行时*
用来表示过去某个时间以前已经开始而又延续到过去这个时间的动作。过去完成进行时也是一个相对的时态，上下文中须有明示或暗示的作为参照的过去时间。过去进行时的形式是had been + doing。
Dick had been smoking for ten years before he decided to give it up last year.

She said she had been expecting your good news.

过去将来时

表示在过去某一时刻之后将要发生的动作或情况，多见于主句谓语动词是一般过去时的宾语从句中。其形式由would或be going to加动词原形构成。
He said that he would get married soon.

一般将来时

用来表示将来发生的动作或情况以及未来的倾向：

将来时的多种表示法：
1.＂shall , will +动词原形＂
We shall start right away .我们马上出发。
They will leave for HongKong tomorrow.他们明天动身去香港。
2.be going +不定式,表示最近打算要做的事情。
What are you going to do this evening ?你今天晚上干什么？
The wall is going to be painted green .这堵墙将被漆成绿色。
3.＂be to do＂表示按计划，日程要发生的事情。　We are to meet at the school gate.我们约定在学校门口见。
There is to be a test in the tenth week.第十周将有一次考试。
4.＂be about +不定式＂表示“正要”，“刚要”发生的动作。
Autumn harvest is about to start .秋收就要开始了。
5.一般现在时表示将来

6.现在进行时表示按计划、安排即将发生的动作

将来进行时
用来表示在将来的某一段时间正在发生的动作。

This time next week she will be working in that company.

I'll be waiting for you at the hotel after supper.

将来完成时
1.用来表示在将来某一时间已经完成的动作。

常与by the end of this month, by then (5 o'clock) , this time next week , by the time, “by+将来时间”等时间状语连用。

We hope it will have stopped raining before we set off for the picnic.

I'll have done all the work by the time you are back this evening.

By the year 2050, scientists probably will have discovered a cure for cancer.
By the time you arrive in London, we will have been staying in Europe for two weeks.