虚拟语气全归纳 四大类别
If虚拟条件句
Wish/if only/would rather愿望 和as if(though)好像
从句中should+动词原形，should可省略
It’s time从句
第一类 If虚拟条件句
分三种时态：与现在事实相反、与过去事实相反、与将来事实相反。
*条件句有真实条件句和非真实(虚拟)条件句两种。真实条件句的假设是有可能发生的，而非真实条件句的假想与事实相反或不大可能会发生，试比较：
If I have time, I will go with them. 假若我有时间，我就同他们去。(陈述语气)
If I were you, I would go with them. 假若我是你，我就同他们去。(虚拟语气)
If条件句虚拟
时态类型
主句
If引导的从句
例句
与现在相反
would/should/could/might+ V原
动词过去式 did
*be 多用were
1. If I were you, I should study English.
2. I would certainly go if I had time.
与过去相反
would/should/could/might + have done
动词过去完成式
had done
1. If you had taken my advice, you would not have failed in the test.
2. If I had left a little earlier, I would have caught the train.
与将来相反
would/should/could/might + V原
①动词过去式
②should +V原
③were + to do
1.If you came tomorrow, we would have the meeting. ①
2. If it were to rain tomorrow, the meeting would be put off.③
*规律总结：从句都往过去推一个时态，如：与现在相反的if从句就用过去时；与过去相反用过去完成时（即过去的过去）
注：几点特别说明
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 wouldn’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,…)
第二类 Wish/if only/would rather愿望 和as if(though)好像从句 分时态
l Wish从句 ……就好了
动词过去式或were—与现在事实相反
主语+wish(that)+主语 + 动词过去完成式—与过去事实相反
助动词过去式+动词原形—与将来事实相反
I wish I were a pop singer. (=I am sorry I am not a pop singer..)
I wish I had never stopped teaching. (=I am sorry I stopped teaching.)
I wish they would let us get some sleep.
* 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.)
l if only 后的句子用虚拟语气 要是……就好了
if 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。
l 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。
l 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)。
第三类 从句中should+动词原形，should可省略
l 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。
l 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
ex.
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。
She desires that he do it. 她希望他做此事。
The general directed that the prisoners should be set free. 将军指示释放那些俘虏。
*suggest表“暗示”insist表“坚持认为”不用虚拟语气
比较：
He insisted that I had read his letter. 他坚持说我看过他的信。
He insisted that I should read his letter. 他坚持要我看他的信。
He suggested that we (should) stay for dinner. 他建议我们留下吃饭。
I suggested that you had a secret understanding with him. 我觉得你与他心照不宣。
l order,suggestion,idea,plan, proposal, advice, demand等名词后的表语从句或同位语从句
Our suggestion is that you（ should）be the first to go． 我们的建议是你应该第一个去。
*advice, agreement, command, decision, decree, demand, determination, indication, insistence, order, preference, proposal, request, requirement, stipulation, suggestion, idea, plan, order
l “It is (was)+ 紧急 重要-- 带感情色彩
上述demand/suggest等动词过去分词 或
important,natural,strange ,necessary，surprised, appropriate等形容词 后的主语从句
1. It is ordered that the army (should) get there by 4 a.m.
2. It is necessary that she (should) be sent there at once.
*It is necessary，important，strange，natural， advisable, anxious, compulsory, crucial, desirable, eager, essential, fitting, imperative(绝对必要), impossible, improper, obligatory, possible, preferable, probable, recommended, urgent, vital etc. ；it is a pity；It is requested/suggested/desired/proposed
第四类 It’s time后的从句用虚拟语气
从句谓语通常用过去式表示 (早)该干某事了
*有时也用过去进行时或“should+动词原形”(较少见，且should不能省略)
ex.
It’s time we went [were going, should go]. 我们该走了。
It’s time I was in bed. 我该上床睡了。(不用were)
It's time = It is (the very/high/right/about) time
