动词三态
动词三态：时态、语态（主动、被动）、语气（陈述、祈使、虚拟）
1、时态总览
英语的动词时态共16种，常用时态（**）有5种，如下单词Wirte为例：
主动语态下的时态：
动词时态
一般
进行
完成
完成进行
过去
Wrote**
Was\were writing*
Had written*
Had been writing
过去将来
Should\would write*
Should\would be writing
Should\would have written
Should\would have been writing
现在
Write/writes**
am\is\are writing**
Has\have written**
Has\have been writing*
将来
Shall\will write**
Shall\will be writing
Shall\will have written
Shall\will have been writing
被动语态（Ask为例，被动式be+过去分词：be asked）下的时态：
动词时态
一般
进行
完成
完成进行
过去
Was\were asked**
Was\were being asked*
Had been asked*
Null
过去将来
Should\would be asked*
Null
Should\would have been asked
Null
现在
Am\is\are asked**
am\is\are being asked**
Has\have been asked**
Null
将来
Shall\will be asked**
Null
Shall\will have been asked
Null
2、特殊时态用法
1）一般将来时：
Will do\shall do多指客观将要发生的动作；
Be going to do 主观打算去做，可能发生的事情；
Be to do 表示计划好的事情（不强调马上做）
Be about to do 表示即将要做某事（时间很接近了，马上去做）
2）一般过去将来时
典型例句：
He said he would be there soon. 他说他很快就到那了。
一般过去将来时也可以用一般将来时里的be(was) going to\be(was) about to do等短语的对应过去时态。
3）过去完成时
过去某时刻以前已经开始并持续到该时刻（到该时刻已经完成）；
4）现在完成时
1、表示过去发生的动作对现在的影响：
2、或表示过去某时间开始的动作一直持续到现在（到现在完成的动作）；
He has lived here since 1949.
5）现在完成进行时
表示动作从过去某一时间开始，一直持续到现在（并可能还要继续进行下去）；
They have been working for two hours.
3、虚拟语气
虚拟语气表主观愿望或假设，其语法是：将假设场景的时态向过去推一级。
1) 虚拟语气在非真实条件句中（表假设）：
虚拟情况
从句
主句
与过去事实相反
（过去完成时）
if+主语+had+过去分词
（过去将来完成时）
主语+would(should\could\might)+have+过去分词
与现在事实相反
（过去时）
If+主语+动词过去式
（过去将来时）
主语+would(should\could\might)+过去原形
与将来事实（可能）相反
（过去时、过去将来时）
If+主语+动词过去式、
should+动词原形、
ware to + 动词原形
（过去将来时）
主语+would(should\could\might)+过去原形
参考时态表：
动词时态
一般
进行
完成
完成进行
过去
Wrote**
Was\were writing*
Had written*
Had been writing
过去将来
Should\would write*
Should\would be writing
Should\would have written
Should\would have been writing
现在
Write/writes**
am\is\are writing**
Has\have written**
Has\have been writing*
将来
Shall\will write**
Shall\will be writing
Shall\will have written
Shall\will have been writing
例子：
(1) 与过去相反：Had it not been for your help,we would not have achieved so much.
有时可以省略if，将were\had\should提前到主语前。还原上述例句为：
If it had not been for your help,we would not have achieved so much.
(2) 与现在相反：If I were you,I would accept his offer. (虚拟语气中be过去式一般用were）
(3) 与将来相反：If it should rain tomorrow,what would you do?
2) 虚拟语气在表示：要求、建议、命令等的名词性从句中，从句谓语用“should+动词原形（过去将来时）
动词：Insist（坚持）、suggest（建议）、order（命令）、propose（建议）、demand（要求）等后面的宾语从句中
He suggested that we should start now.
名词：insistence\suggestion\order\proposal\demand等后面的表语从句或同位语从句中
Their suggestion is that their output should be inceased by 20%.
主语从句：It+be+(natural\necessary\strage\important or insistend\suggested\ordered)+that...
It’s necessary that you should be present at the meeting.
3) 虚拟语气在wish后面的宾语从句
过去 that + 主+had+过去分词
现在 that + 主+过去式
将来 that + 主+would\might+动词原形
eg: I wish (that) I knew the answer.
