虚拟语气是英语中常出现的一种语言现象，近几年成了高考语法题中的一个热点。每年都有不少省份高考试题中考到这一考点。对于许多中国学生来说，它也是一个难点。无怪乎许多学生学完虚拟语气后，常常会叹道：If there were no subjunctive mood（虚拟语气）, English ______ much easier.A. will be B. would have been C. could have been D. would be这就是个有关虚拟语气的题目，本题答案选什么呢？本文要来解答这个问题。让我们来看看虚拟语气有哪些常见的重要考点
考点一非真实条件句中的虚拟语气
考例1.If he______ my advice, he wouldn"t have lost his job.
A. followed B. should follow C. had followed D. would follow
【分析】C。本题考查的是与过去事实相反的非真实条件句中虚拟语气的用法。根据主句中的时态为过去将来完成时，那么对应的条件句中就应该使用过去完成时，所以答案为C。
【方法技巧】在含有if非真实条件句的虚拟语气中，if从句与主句的谓语动词变化规则是：
如何轻松记住这些规则并运用自如呢？大家可记这个口诀。即“现/过/过将，过/过完/过将完，将/过/过将。”“现”即虚拟与现在事实相反的情况，“过”则表示if从句中的谓语动词用过去时（动词过去式），“过将”则表示主句谓语动词使用过去将来时（would do）；“过过完过将完”则表示虚拟与过去事实相反的情况时，if 从句中的谓语动词用过去完成时（had done），主句中的谓语动词用过去将来完成时（would have done）；“将过将过将”则表示虚拟与将来事实相反的情况时，if从句中的谓语动词使用过去式［注：另外的两种形式should do或were to do亦可］，主句中的谓语动词也使用过去将来时（would do）。
那么，在本文前面提到的那个题目应该选什么呢？这是与现在事实相反的虚拟语气，条件句是过去时，对应的口诀是现/过/过将，应使用过去将来时，我们可知答案为D。
考例2. This printer is of good quality. If it _______ break down within the first year, we would repair it at our expense.
A. would B. should C. could D. might
【分析】B。本题考查的是与将来事实相反的非真实条件状语从句中虚拟语气的用法。根据上面的表格以及变化口诀可知，本题中主句为过去将来时，if从句对应的时态应该使用过去时或were to+动词原形或should+动词原形，故答案只能选B。
考例3. I am not free today. If I _____free today, I _____ and visit some of my friends.
A. am, will go B. were, would go C. were, shall be D. be, must go
【分析】B。根据句中的关键词today可知，本题考查的是与现在事实相反的虚拟语气的用法。根据上面的表格以及变化口诀可知，本题中if从句对应的应该使用过去时，主句为过去将来时，故答案只能是选B。
考点二 错综时间虚拟条件句
考例4. Maybe if I _____ science, and not literature then, I would be able to give you more help.
A. studied B. would study C. had studied D. was studying
【分析】C。本题中主句和从句与不同时间的事实相反。主句用的过去将来时，说明是与现在事实相反，但从句中有一个过去时间then，根据上下文来看，从句是与过去事实相反，所以应该使用对应的过去完成时。所以答案为Ｃ。
【方法技巧】当从句与主句或上下文所表述的时间不一致时，我们切不可照搬某种形式，而应该按照句中所表述的时间关系，再选择相应的虚拟形式。再如：
If you had worked hard yesterday, you would be tired now.（注意主句与从句的不同时间）
考例5. I ______ sooner but I didn’t know that they were waiting for me.
A. had come B. was coming C. would come D. would have come
【分析】Ｄ。根据but后面句子的意思可知这是一个过去的客观事实，那么前句就是一个与过去事实相反的主句了,所以要使用过去将来完成时。本句可以理解为If I had known that they were waiting for me, I would have com sooner. But I didn’t know that they were waiting for me.
考点三 省略if情况
考例6. Had I known about this computer program, a huge amount of time and energy_________ .
A. would have been saved B. had been saved
C. will be saved D. was saved
【分析】A。本题中的前面句子是一个省略if后再把had提前的从句。根据从句中使用的是过去完成时，说明是一个与过去事实相反的虚拟语气，那么主句中就对应使用过去将来完成时。所以答案选Ａ。
【方法技巧】若虚拟条件句中有 were, had, should 时，可省略 if 而将 were, had, should 移到句首。
考点四 名词性从句中的虚拟语气
1）宾语从句中的虚拟语气
考例7. Teachers recommend parents_______their children under 12 to ride bicycles to school for safety.
A. not allow B. do not allow C. mustn’t allow D. couldn’t allow
【分析】Ａ。本题中的关键词是recommend是“推荐；建议”的意思，在后面接宾语从句时应该使用should+do，其中should可以省略。故答案为Ａ。
【方法技巧】在某些动词后的宾语从句中需用should+动词原形的虚拟语气形式。“should”可以省略。常见的动词有：一个坚持insist；两个命令order， command ； 三条建议suggest， advise， propose； 六项要求demand， request， require， ask， urge， desire。注意：suggest表“暗示，表明”时， insist表“坚持认为”时不用虚拟语气。
2）主语从句中的虚拟语气
考例8. _____ in the regulations that you should not tell other people the password of your e-mail account.
A. What is required B. What requires C. It is required D. It requires
【分析】C。本题考查的是主语从句中含有required（要求）的虚拟语气的用法，从句中也要使用should+do，其中should可以省略。
【方法技巧】主语从句中的虚拟语气基本句型有：1. It be+过去分词+that…+(should)+动词原形+…过去分词：suggested, requested, ordered, proposed, demanded, arranged, desired, advised如：It’s suggested that everybody (should) buy a dictionary.2. It be+形容词+that…+(should)+动词原形+…形容词:important, necessary, natural, right, wrong, better, proper, funny, strange, surprising…如：It is necessary that we (should ) have a walk now.3. It be+名词（ a pity/a shame/ no wonder） that… + (should)+动词原形+…如：It seems such a pity that you should have to spend the day at the hotel.
3）表语从句、同位语从句中的虚拟语气
考例9. His suggestion that you _____ once more sounds reasonable.
A. try B. tries C. must try D. can try
【分析】A。本题考查的是同位语从句中的虚拟语气的用法。因句中也含有suggestion（建议），从句中要使用should+do，其中should可以省略。
【方法技巧】某些表示“建议、请求、命令”等意义的名词后的表语从句或同位语从句需用“（should）＋动词原形”构成谓语。这类名词有：advice，desire，decision， idea，order，plan，proposal，recommendation，request，suggestion等，如：His recommendation is that we（should）go there by train．
考点五 几种特殊句式的虚拟语气:
1）would rather+从句
考例10. George is going to talk about the geography of his country, but I’d rather he______ more on its culture. (2010年江苏)
A. focus B. focused C. would focus D. had focused
【分析】B。本题考查的是would rather后接从句时使用虚拟语气的用法。从句与现在事实相反时，动词时态要使用过去时。
【方法技巧】would rather+ 句子(虚拟) 一般过去时 对现在虚拟过去完成时 对过去虚拟一般过去时 对将来虚拟①I would rather you posted the letter right away.②I would rather you had returned the book yesterday.③Don’t come tomorrow. I’d rather you came next weekend.
2）wish+从句
考例11. ----Where are the children? The dinner’s going to be completely ruined. (2011北京)
----I wish they _____ always late.
A. weren’t B. hadn’t been C. wouldn’t be D. wouldn’t have been
【分析】Ａ。本题考查的是wish后接从句时的虚拟语气用法。题目中是与现在事实相反，所以对应的动词使用过去时。
【方法技巧】wish 后的宾语从句，若表示不能实现的愿望，谓语动词用过去时表示与现在事实相反的愿望；用过去完成时表示与过去事实相反的愿望；用“would ／could ／might＋动词原形”表示与将来可能发生的事情相反的愿望。
考点六 句型It is (high, about, low) time that从句
考例12. It’s about time he ______ to do the work.
A. begins B. will begin C. begin D. began
【分析】D。本题考查的是It is (high, about, low) time that从句中的虚拟语气的用法。从句后面使用过去时或should + do，其中should不能省。
考点七 含蓄式虚拟语气
考例13. We ______ John’s name on the race list yesterday but for his recent injury.
A. will put B. will have put C. would put D. would have put
【分析】D。本题考查的是含有but for 的含蓄式虚拟语气的用法。根据题意可知，主句应是与过去事实相反的虚拟语气，所以对应的要用过去将来完成时。
【方法技巧】1）用介词短语without，but for （要不是）等表示条件。如：Without air and water (If there were no air and water), all living things on the earth would die．地球上如果没有空气和水，一切生物都将死亡。2）用连词or, otherwise, but, once, though等表示条件。如：He was taken to hospital at once yesterday, otherwise ／ or he would have died already． ＝ If he had not been taken to hospital at once yesterday, he would have died already．昨天他被立即送到了医院，要不然他早就死了。
3）用分词短语表示条件。如：
Given more time, we could have done the task much better． ＝ If we had been given more time, we could have done the task much better．如果再给我们点时间，我们会做得更好。
4）if only 若是...那该多好啊; 真希望...; 只要...就好，如：
If only he had lain quietly as the doctor instructed, he would not suffer so much now.
