英语的动词有三种语气形式

语气用来说明事实或就事实提出询问，可用于陈述句、疑问句和某些感叹

注：特别说明

1、l would/should/could/might主句谓语中的should主要用于第一人称后；would表示结果还表示过去经常常常做某事，might表示可能性，could表示能力、允许或可能性。比较：

If you tried again ，you would succeed. 要是你再试一试，你就会成功的。(would表结果)

If you tried again， you might succeed. 要是你再试一试，你可能会成功的。(might表可能)

If you tried again ，you could succeed. 要是你再试一试，你就能成功了。(could表能力)

2、错综时间虚拟条件句即条件从句与主句所指时间不一致，如从句指过去，而主句即指的是现在或将来，此时应根据具体的语境情况，结合上面提到的三种基本类型对时态作相应的调整：

If it had rained last night, the ground would be wet now. 要是昨晚下过雨的话，现在地面就会是湿的。

You would be much better now if you had taken my advice. 假若你当时听我的话，你现在就会好多了。

3、If虚拟条件句的否定（含蓄条件句）常考两个句型：If it weren’t for…和If it hadn’t been for…，其意为“若不是(有)” “要不是”。如：

If it weren’t for water, no plant could grow. 要是没有水植物就无法生长。

If it hadn’t been for your assistance ，we wouldn’t have succeeded.

=But for your assistance ，we wouldn’t have succeeded.

=Without your assistance ，we woul dn’t have succeeded.

4、If虚拟条件句的倒装形式，即把were, had, should置于句首。例：

Were I in school again (= If I were in school again), I would work harder.

Had you asked me, I would have told you. (=If you had asked me,…) 编辑本段第二类

使用虚拟语气的常见结构或从句：

1.*wish与hope接宾语从句的区别在于：hope表示一般可以实现的希望，宾语从句用陈述语气。wish表示很难或不大可能实现的希望,宾语从句用虚拟语气。试比较：

（1）We hope they will come. (We don’t know if they can come.) （2） We wish they could come. (We know they are not coming.) only 与 I wish一样，也用于表示与事实相反的愿望，其后所虚拟语气的时态与 wish后所接时态的情况相同：

If only she had had more courage! 她再勇敢一些就好了。

If only I had listened to my parents! 我要是当时听了父母的话就好了。

If only she would go with me! 她要是愿意和我一道去就好了!

*if only 通常独立使用，没有主句。

would rather后句子用虚拟语气只分现在和过去

在would rather, would sooner, would just as soon后的that从句中, 句子谓语习惯上要用虚拟语气，表示"宁愿做什么" ，具体用法为：

①一般过去时表示现在或将来的愿望

I’d rather you went tomorrow (now). 我宁愿你明天(现在)去。

②用过去完成时表过去的愿望

I’d rather you hadn’t said it. 我真希望你没有这样说过。

as if (though)从句用虚拟语气

以as if (as though)引导的方式状语从句或表语从句，有时用虚拟语气,则与wish用法相同，例：

He acts as if he knew me. 他显得认识我似的。

They treat me as though I were a stranger. 他们待我如陌生人。

He talks as if he had been abroad. 他说起话来好像曾经出过国。

注：两点说明

(1) 从句所表示的内容若为事实或可能为事实，也可用陈述语气：

It looks as if we’ll be late. 我们似乎要迟到了。

(2) 注意It isn’t as if…的翻译：

It isn’t as if he were poor. 他不像穷的样子(或他又不穷)。

编辑本段第三类

从句中should+动词原形，should可省略

1. 在lest ，for fear that( 以免) ,in case(以防)引导的目的状语从句中的虚拟语气

She walked quietly lest she (should)wake up her roommates. 她走得很轻以免吵醒她的室友。

2. 表应当做值得做一类动词后的宾语从句

建议advise, suggest, propose, recommend命令order, command 请求ask, demand, require, request指示direct

敦促urge提议move, vote

希望desire坚持insist

打算intend安排arrange

例如：

I insisted that he (should)stay. 我坚持要他留下。

He urged that they go to Europe. 他敦促他们到欧洲去。

He suggested that we should leave early. 他建议我们早点动身。

He ordered that it (should)be sent back. 他命令把它送回去。

I ask that he leave. 我要求他走开。

He requires that I (should)appear. 他要求我出场。

I move that we accept the proposal. 我提议通过这项提案。

He arranged that I should go abroad. 他安排我去国外。