虚拟语气的用法

虚拟语气的用法
虚拟语气（The Subjunctive Mood）表示说话人所说的话不是事实，而是一种假设、愿望、怀疑或推测。

1. 虚拟语气在if条件状语从句中的用法：
条件句
从句中谓语的形式
主句谓语的形式
表示现在情况
动词过去式（be的过去式用were）
should / would / might / could +动词原形
表示将来情况
should +动词原形；
were to +动词原形；
动词过去式（be的过去式用were）
should / would / might / could +动词原形
表示过去情况
had +过去分词
should / would / might / could + have + 过去分词
如：If John had time, he would attend the meeting.
If it were to / should rain / rained tomorrow, the meeting would be put off.
If you had come yesterday, you would have met Jim.
2. 虚拟语气在as if / though引导的方式状语从句中的用法：
在as if / though引导的方式状语从句中，谓语动词常用虚拟语气，其形式与wish后宾语从句的谓语动词用法相似。

如：
You treat the elderly as if / though they were your parents.
He behaved as if / though nothing had happened.
3. 虚拟语气在宾语从句中的用法：
①wish后宾语从句中的用法：
宾语从句
wish后宾语从句中谓语的常见形式
表示现在情况
动词过去式（be的过去式用were）
表示将来情况
would / could / might +动词原形
表示过去情况
had + 过去分词
如：I wish I were a bird!
I wish I could be with you for the next three months.
We wish we had done better in our work.
②虚拟语气在would rather后宾语从句中的用法：
宾语从句
would rather后宾语从句中谓语的常见形式
表示现在或将来情况
动词过去式（be的过去式用were）
表示过去情况
had +过去分词
如：He’d rather his children did not make so much noise.
I’d rather you came again the day after tomorrow.
I’d rather you had not done that.
③虚拟语气在某些动词后的宾语从句中的用法：
在表示坚持、愿望、建议、命令、请求等动词后的宾语从句中，谓语动词常用“（should +）动词原形”。

为了便于记忆可归纳为：一个“坚持（insist）”，两个“命令（order, command）”，三个“建议（advise, suggest, propose）”，四个“要求（demand, desire, request, require）”。

如：
Lucy insisted that she (should) go abroad.
The doctor suggested that I (should) stay in bed for another week.
注意：当insist表示“坚持认为，坚持说”时，后接的从句不用虚拟语气；当suggest表示“暗示，表明”时，后接的从句也不用虚拟语气。

如：
We insisted that we had never learned this word before.
His silence suggests that he agrees with me.
4. 虚拟语气在含蓄条件句中的用法：
虚拟的条件有时可以不用条件从句来表示，而是暗含在某些词、短语或上下文中。

常见的词或短语有without, or, otherwise, but for等。

如：
Without the message, I would not have found the lost computer.
I went over all my notes; otherwise I couldn’t have done so well in the exam.
But for your help, we couldn’t have finished the work ahead of time.
5. 虚拟语气在错综时间条件句中的用法：
有时候，条件状语从句的谓语和主句的谓语所表示的动作在时间上并不一致，这类句子称为错综时间条件句。

此时，主句和从句的谓语动词要根据各自所指的不同时间选用适当的虚拟语气形式。

如：
If you had taken my advice, you wouldn’t be in such t rouble now.
If he had been trying hard, his parents wouldn’t be so worried.
6. 虚拟语气的其它用法：
①在“It is +（表愿望、建议、命令、要求、惊讶、怀疑、不满、必要性、重要性等意义的）形容词/过去分词/名词+ 从句”结构中，从句的谓语动词常用“（should +）动词原形”。

如：
It is strange that he (should) have so many friends.
It’s neces sary that the problem (should) be settled immediately.
It is recommended by the doctor that I (should) give up smoking.
It’s a shame that she (should) behave like that.
②在表示请求、建议、要求、愿望、命令等意义的名词（如request, suggestion, proposal, desire, order等）后面的同位语从句中，谓语动词常用“（should +）动词原形”。

如：
My suggestion is that we (should) send a few students to help the other groups.
The captain has given orders that it (should) be done.
③在It is (high / about) time后的定语从句中，谓语动词用虚拟语气，多用过去式，意为“该干……了”。

如：
It is high time that we took measures to protect these endangered animals.
It is time that you made up your mind.
④在if only（但愿，要是……就好了）引导的非真实条件句中，谓语动词常用虚拟语气，其谓语动词形式与wish后宾语从句的谓语动词用法相同。

如：
If only our teacher were here!
If only we hadn’t telephoned him in advanc e.
If only the rain would stop!
⑤在非真实条件句中，连词if的省略
如果if条件句使用的是虚拟语气，且谓语中有had，should，were的话，可将if省略，同时将had，should，were提到主语之前。

如：
Should he consider the problem carefully, he might come to the correct conclusion.
Had you informed me earlier, I wouldn’t have signed the agreement.
Were I to do the experiment, I should read the instructions carefully.
⑥may用在独立句中表示祝愿，动词用原形。

如：
May our friendship last forever!。