一、考查虚拟语气在条件从句中的用法
虚拟语气在条件从句中的用法是其最基本的用法，也是高考最可能涉题的用法。为了便于理解和记忆，我们虚拟语气在虚拟条件从中的用法分为三类--涉及现在时间的虚拟条件，涉及过去时间的虚拟条件，涉及将来时间的虚拟条件。下面就是这三类基本句型的谓语动词形式：
时间 从句谓语形式 主句谓语形式
将来 一般过去时(be用were) would/should/might/could+动词原形
现在 一般过去时(be用were) would/should/might/could+动词原形
过去 过去完成时 would/should/might/could have+过去分词
【有关考题】（答案分别为CBD）
(1) If he _______ my advice, he wouldn’t have lost his job. (2010湖南卷)
A. followed B. should follow C. had followed D. would follow
(1) If we _______ the other road, we might have arrived here in time for the meeting. (2010陕西卷)
A. taken B. had taken C. took D. have taken
(1) -John went to the hospital alone.
-If he _______ me about it, I would have gone with him. (2010天津卷)
A. should tell B. tells C. told D. had told
二、考查特殊句型中的虚拟语气
英语中需要使用虚拟语气的特殊句型不多，主要有以下类：
1. “倒装”类虚拟语气
当虚拟条件句中含有were, should, had时，有时可将引导虚拟条件句的连词if省略，而将从句中的were, should, had 提到句首，构成倒装形式的虚拟语气。如：
If he were here, she would agree too. →Were she here, she would agree too. 如果她在这里，她也同意的。
If it should rain tomorrow, we should have to put off the match. →Should it rain tomorrow, we should have to put off the match. 假若明天下雨，我们只好推迟这场比赛。
If we had found him earlier we could have saved his life.→Had we found him earlier we could have saved his life. 要是我们当时早点找到他的话，我们就可以救活他。
注意，如果条件从句的谓语为否定式，其中的否定词not应置于主语之后，而不能与were, should, had 等缩略成Weren’t, Shouldn’t, Hadn’t而置于句首。如：我如不是警告了你，你就可能丧命了。
正：If I hadn’t warned you, you could have been killed. 正：Had I not warned you, you could have been killed.
误：Hadn’t I warned you, you could have been killed. 另外，有时省略if后提前到句首的had可能不是助动词，而是实义动词。如：Had I time, I would go with you. 假如我有时间，我就同你们一起去。句中的had不是构成过去完成时的助动词，而是表示“有”，如果不省略if，其完整形式为：If I had time, I would go with you.
【有关考题】（答案分别为AB）
(1) Had I known about this computer program, a huge amount of time and energy _______. (2010浙江卷)
A. would have been saved B. had been saved C. will be saved D. was saved
(1) _______ fired, your health care and other benefits will not be immediately cut off. (2006湖北卷)
A. Would you be B. Should you be C. Could you be D. Might you be
3. “宁愿”类虚拟语气
这里说的“宁愿”主要是指would rather。当它后接句子的时候，句子的谓语通常要用虚拟语气，其用法及结构形式为：若从句内容是涉及的是对现在或将来情况的希望，则从句谓语用一般过去时；若从句内容是涉及的是对过去已发生情况表示遗憾或后悔，则从句谓语用过去完成时。如：
I’d rather you went home now. 我希望你现在就回家。
Tomorrow’s difficult. I’d rather yon came next weekend. 明天有困难，我希望你下周末来。
I’d rather I had gone to the theatre last night. 我倒希望我昨晚我去了剧院看戏。(zn)
【有关考题】（答案为B）
George is going to talk about the geography of his country, but I’d rather he _______ more on its culture. (2010江苏卷)
A. focus B. focused C. would focus D. had focused
4. “建议”类虚拟语气
但是，若suggest表示“暗示”“表明”“指出”“提出(看法)”等，则从句谓语要用陈述语气。如：
His smile suggested that he was satisfied. 他的微笑表明他是满意的。
【有关考题】（答案为A）
Teachers recommend parents _______ their children under 12 to ride bicycles to school for safety. (2010福建卷)
A. not allow B. do not allow C. mustn’t allow D. couldn’t allow
【有关考题】（答案为C）
The workers will go on strike if the demands they _______ put forward are turned down. (2006福建卷)
A. could B. would C. 不填 D. had
答案为C。
7. “坚持”类虚拟语气
这类虚拟语气主要指动词insist后接宾语从句时所用的虚拟语气--若从句内容是既成的事实，不容置疑，则从句谓语用陈述语气，此时insist的意思是“坚持说”；若从句内容虽然还不是事实，但非常希望它成为事实，从句谓语用虚拟语气，即采用“should+动词原形”的形式，且其中的should在美国英语中可以省略，此时insist的意思是“坚持要”。比较并体会：
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 insisted that he was not ill, but the doctor insisted that he should take the medicine. 他坚持说他没有病，但医生却坚持要他服药。
8. “愿望”类虚拟语气
这类虚拟语气主要指动词wish和固定搭配if only后所接从句使用的虚拟语气，但不包括动词hope在内。此类虚拟语气的结构特点如下：
从句所涉及时间 从句谓语形式
从句内容涉及现在情况 一般过去时 / 过去进行式
从句内容涉及过去情况 过去完成时 / would (could)+have +过去分词
从句内容涉及将来情况 would (could, might)＋动词原形
I wish I could swim. 我要是会游泳就好了。
I wish I had been here yesterday. 我真希望我昨天在这里。
I wish he could come tomorrow. 我希望他明天能来。
I wish you would come if you had time. 你如有时间的话，我希望你来。
If only I knew her name! 我要是知道她的名字就好了!
If only you had let me know earlier. 要是你早点让我知道就好了。
If only she would go with me! 她要是愿意和我一道去就好了!
9. “似乎”类虚拟语气
这类虚拟语气主要指由表示“好像”和“似乎”的as if以及as though引出的虚拟语气句子。既然是“好像”怎么样，或者是“似乎”怎么样，所以它描述的内容就不大可能是事实，或者说可能是非真实的，所以它的谓语通常要用虚拟语气，其结构形式与wish后从句的谓语形式差不多。如：
I’ve loved you as if you were my son. 我爱你就像我的儿子。
He talks as if he had a potato in his mouth. 他讲起话来仿佛嘴里含了一个土豆似的。
She looked as if she had seen a ghost. 她看起来好像刚才遇见了鬼似的。
根据各句的句意可知，“你”显然不是“我”的儿子，所以第一句中as if从句的内容是非真实的，故用虚拟语气；“他”说话的时候嘴里肯定没有含一个土豆，所以第二句中as if从句的内容也是非真实的，故也用虚拟语气；大家知道“鬼”是不存在的，所以她好像见到鬼的内容也是不真实的，所以第三句的as if从句也用虚拟语气。
但是，如果说话者认为as if或as though从句所表示的内容是真实的，或者说是有可能成为事实的，那么也可以使用陈述语气。如：
We’ve missed the bus. It looks as if we’ll have to walk. 我们错过了公共汽车，看来我们得走路了。
10. “时候”类虚拟语气
这类虚拟语气主要是指It’s time…（是做某事的时候了）后接从句时所使用的谓语形式--不管是针对现在还是将来的情况，一律使用一般过去时。如：
It’s time we ordered dinner. 现在该叫菜了。
It’s time you washed those trousers. 你该洗洗那条裤子了。
I’m getting tired. It’s time we went home. 我累了，我们该回家了。
另外，有时还可在名词time前加上修饰语high表示强调。如：
It’s high time you bought a new car. 你早该买辆新车了。
有一点值得注意，就是动词be在这类虚拟语气中的用法与其他的虚拟语气结构不同，前面我们讲到动词be在虚拟语气句式中通常在该用was的时候而用were，但是it’s time后的从句中，该用was的时候不能用were来代替。如：
大家都该上床睡觉了。
误：It’s time everyone were in bed. 正：It’s time everyone was in bed.
11. “若不是”类虚拟语气
英语中有三个表示“若不是”“要不是”的固定表达，它们总是用于引出虚拟条件，句子谓语总是用虚拟语气。这三个固定表达是but for, if it were not for, if it had not been for。如：
The car broke down. But for that we would have been in time. 汽车出毛病了。要不是那个我们会及时赶到的。
If it weren’t for your help, I would still be homeless. 若非你的帮助，我仍会无家可归。
If it hadn’t been for the doctor’s care, I wouldn’t have recovered so soon. 要不是医生的照顾，我不会痊愈得这么快。注：介词without有时也可表示虚拟条件，意为“若不是”“要不是”，与but for用法相同。如：
Without [=But for] your help, I would have failed. 要不是有你的帮助，我就会失败了。
但是，without也可以不表示条件，只表示“没有”的意思。如：
Without a word he left the room. 没有说一句话他离开了房间。
【有关考题】（答案分别为BD）
(1) But for the help of my English teacher, I ________ the first prize in the English Writing Competition. (2009福建卷)
A. would not win B. would not have wonC. would win D. would have won
(2) But for their help, we ________ the program in time. (2009安徽卷)
A. can not finish B. will not finish
C. had not finished D. could not have finished