英语虚拟语气学习指导
英语虚拟语气一直受到语言学家及语法学家们的关注。他们从各个方面对虚拟语气进行了分析，包括给虚拟语气下定义，进行分类，讨论其在交际中的功能，甚至也争论其存在的价值，而随着语言学发展，虚拟语气的意义构建成为研究重点。学好虚拟语气对于学习英语的整体有着极大的帮助!
英语虚拟语气学习指导1.虚拟语气在条件句中的用法
(1)若表示与现在事实相反的假设，则条件从句中用过去式，主句中用过去将来式(would，should，could，might + 动词原形);若表示某事将来实现的可能性不大，则条件从句中用should + 动词原形也可用“were to+动词原形”或用过去式动词。
I would certainly go if I had time.(现在)
If it should rain，we wouldn’t go out.(将来)
If I knew German，I would read the paper to you.(现在)
If he were here，we could ask him.(现在)
(2)若表示与过去事实相反的假设，从句中用过去完成式，主句中用过去将来完成式(should，would，could，might + have + 过去分词)。
If Ihad set off a little earlier，I would have caught the train.
Shewould / might have come if she hadn’t been so busy.
If I hadn’t taken your advice，I wouldhave made a bad mistake.
If only you hadn’t told him the news.
(3)含有虚拟语气的条件状语从句中，如有had，should，were这三个词的话，在正式或书面语言中可将if省略，再将句子的主语和谓语动词实行全部倒装或部分倒装。如：
Had they time(=If theyhad time)，they would certainly come and help us.
Should it be fine(=If it should be fine)，we would go for an outing.
Were I go(=If Iwere you)，I would go.
(4)若主句从句所指的时间不一致，即条件从句表示与过去事实相反，主句表示与现在事实相反;或者条件从句表示与现在事实相反，主句表示真实情况，则从句中应采用与具体时间相对应的虚拟形式。
If ithad rained last night(过去)，It would be very cold today(现在).
If Ihad taken your advice(过去)，I should have no trouble with the work now(现在).
英语虚拟语气学习指导2. 条件句中的虚拟语气的举例
(1) 将来时的条件句中的虚拟语气。
If he should go to Qing Hua University, he would make full use of his time. 如果他要上清华大学的话，他就会充分利用他的时间了。
If he were to come here, he would tell us about it. 如果他要来的话，他会通知我们一声。
(2) 现在时的条件句中的虚拟语气。
If he were free, he would help us. 要是他有空的话，它会帮助我们的。
If he studied at this school, he would know you well. 如果他在这所学校学习的话，它会对你很熟悉。
(3) 过去时的条件句中的虚拟语气。
If I had seen the film, I would have told you about it. 我如果看过这场电影，我会把电影内容告诉你了。
If I had got there earlier, I would have met Mr. Li. 如果我早点到那儿，我就会会到了李先生。
英语虚拟语气学习指导3. 运用条件句中的虚拟语气时，须注意的几个问题
(1) 当从句的主语为第三人称单数时，谓语动词若是系动词be时，可用was 代替were。但在倒装虚拟结构及if I were you, as it were中，只能用were。
Were I ten years younger, I would study abroad. 要是我还年轻十岁的话，我会去国外学习。
If I were you, I would try my best to grasp the chance. 要是我是你的话，我要尽力抓住这次机会。
(2) 有时，虚拟条件句中，主、从句的动作若不是同时发生时，须区别对待。
①从句的动作与过去事实相反，而主句的动作与现在或现在正在发生的事实不符。
If I had worked hard at school, I would be an engineer, too. 如果我在学校学习刻苦的话，我现在也会使工程师了
If they had informed us, we would not come here now. 如果他们通知过我们的话，我们现在就不会来这里了。
②从句的动作与现在事实相反，而主句的动作与过去事实不符。
If he were free today, we would have sent him to Beijing. 如果他今天有空的话，我们会已经派他去北京了。
If he knew her, he would have greeted her. 要是他认识她的话，他肯定会去问候她了。
③从句的动作与过去发生的情况相反，而主句的动作与现在正在发生的情况相反。
If it had not been raining too much, the crops would be growing much better. 如果天不下太多的雨的话，庄家会长得更好。
If he had been working hard, he would be working in the office now. 要是他工作一直努力的话，他现在已进了办公室了。
英语虚拟语气学习指导4、虚拟语气的用法及动词形式
一、表示与现在事实相反的情况：
从句：If 主语+过去时(Be动词用were)
主句：主语+should/would/could/might+do
eg：
1.If I were you,I would take an umbrella.
如果我是你，我会带把伞。(事实：我不可能是你)
2.If I knew his telephone number,I would tell you.
如果我知道他的电话号码，我就会告诉你。(事实：不知道)
3.If there were no air or water,there would be no living things on the earth.
如果没有水和空气，地球上就不会有生物。(事实：地球上既有空气也有水)
4.If I had any money with me,I could lend you some.
如果我带钱了，我就会借给你些。(事实：没有带钱)
5.If he studied harder,he might pass the exam.
如果他再努力些，就能通过考试了。(事实：没有努力)
(注意：一般在虚拟的条件句中无论是第几人称，用到系动词的过去式时，只用were而不用was)
二、表示与过去事实相反的情况
从句：If 主语+had+done
主句：主语+should/would/could/might+have done
eg：
1. If I had got there earlier,I should/could have met her. 如果我早到那儿，我就会见到她。
(事实：去晚了)
2.If he had taken my advice,he would not have made such a mistake. 如果他听我的劝告的话，就不会犯这样的错误了。
(事实：没有听我的话)
3.she looked at me as if I had been a stranger.
她看我的样子好像我是一个陌生人。(事实：我并非陌生人)
三、表示对将来情况的主观推测
主句：主语+would+do
从句：①if+主语+were to do
②if+主语+should/would/could/might+do
③if+主语+did(动词过去式)/were
eg：
1.If he should come here tomorrow,I would talk to him.
如果他明天来这儿的话，我就跟他谈谈。(事实：来的可能性很小)
2.If there were a heavy snow next Sunday,we would not go skating.
如果下周日下大雪，我们就不能去滑冰了。(事实：下雪可能性很小)
3.If she were to be here next Monday,I would tell her about the matter.
如果她下周一来这儿的话，我就会告诉她这件事的始末。(事实：来的可能性很小)
四、 有时，虚拟条件句中，如果主句和条件从句的谓语动作若不是同时发生时，虚拟语气的形式应作出相应的调整。这种条件句叫错综条件句。
①从句的动作与过去事实相反，而主句的动作与现在或现在正在发生的事实不符。
eg：
If I had worked hard at school,I would be an engineer,too.
如果我在学校学习刻苦的话，我现在也会成为一个工程师了
If they had informed us,we would not come here now.
如果他们通知过我们的话，我们现在就不会来这里了。
②从句的动作与现在事实相反，而主句的动作与过去事实不符。
如：
If he were free today,we would have sent him to Beijing.
如果他今天有空的话，我们会已经派他去北京了。
If he knew her,he would have greeted her.
要是他认识她的话，他肯定会去问候她了。
五、 当虚拟条件句的谓语动词含有were,should,had时，if可以省略，这时条件从句要用倒装语序，即把were,should,had等词置于句首，这种多用于书面语。eg：
Should he agree to go there,we would send him there.
要是他答应去的话，我们就派他去。
Were she here,she would agree with us.
如果她在这儿的话，她会同意我们的。
Had he learnt about computers,we would have hired him to work here.
如果他懂一些电脑知识的话，我们已经聘用他来这里工作了。
六、非真实条件句中的条件从句有时不表达出来，只暗含在副词、介词短语、上下文或其他方式表示出来，这种句子叫做含蓄条件句，在多数情况下，条件会暗含在短语中，如without…，but for…等
eg：
But for his help,we would be working now.
要不是他的帮助，我们还会在工作呢。
Without your instruction,I would not have made such great progress.
要是没有你的指导，我不会取得如此大的进步。
We didn't know his telephone number,otherwise,we would have telephoned him.
我们不知道他的电话号码，否则我们就会给他打电话。
七、 有时，虚拟条件句中，主、从句可以省略其中的一个，来表示说话人的一种强烈的感情。
①省略从句
He would have finished it. 他本该完成了。
You could have passed this exam. 你本能通过这次考试的。
②省略主句
If I were at home now. 要是我现在在家里该多好啊。
If only I had got it. 要是只有我得到它了该多好啊。
八.注意，在虚拟语气的从句中，动词be的过去时态一律用were，不用was。
eg：If I were you,I would go to look for him.
如果我是你，就会去找他。