虚拟语气的具体用法
1.概念
虚拟语气用来表示说话人的主观愿望或假想，所说的是一个条件，不一定是事实，或与事实相反。
2.在条件句中的应用
条件句可分为两类，一类为真实条件句，一类为非真实条件句。非真实条件句表示的是假设的或实际可能性不大的情况，故采用虚拟语气。
真实条件句
真实条件句用于陈述语气，假设的情况可能发生，其中if是“如果”的意思。
时态关系
句型：条件从句+主句
一般现在时：shall/will + 动词原形
If he comes, he will bring his violin.
注意：
1）在真实条件句中，主句不能用be going to表示将来，该用shall, will.
2）表示真理时，主句谓语动词便不用shall (will) +动词原形，而直接用一般现在时的动词形式。
非真实条件句
时态：可以表示过去，现在和将来的情况。它的基本特点是时态退后。
a.同现在事实相反的假设。
句型：条件从句+主句
一般过去时：should(would)+动词原形
If they were here, they would help you.
b.表示于过去事实相反的假设。
句型：条件从句+主句
过去完成时：should(would)have+ 过去分词
If she had worked harder, she would have succeeded.
The rice would not have been burnt if you had been more careful.
If my lawyer had been here last Saturday, he would have prevented me from going.
If he had come yesterday, I should / would have told him about it.
含义：He did not come yesterday, so I did not tell him about it.
If he had not been ill and missed many classes, he would have made greater progress.
含义： He was ill and missed many lessons, so he did not make greater progress.
c.表示对将来的假想
句型：条件从句+主句
一般过去时：should+动词原形/were+不定式/would+动词原形/should+ 动词原形
If you succeeded, everything would be all right.
If you should succeed, everything would be all right.
If you were to succeed, everything would be all right.
混合条件句
主句与从句的动作发生在不同的时间，这时主，从句谓语动词的虚拟语气形式因时间不同而不同，这叫做混合条件句。
If you had asked him yesterday, you would know what to do now.
（从句与过去事实相反，主句与现在事实相反。）
If it had rained last night (过去), it would be very cold today (现在).
虚拟条件句的倒装
虚拟条件句的从句部分如果含有were、should、或had可将if省略，再把were、should或had移到从句句首，实行倒装。
Were they here now, they could help us. = If they were here now, they could help us.
Had you come earlier, you would have met him. = If you had come earlier, you would have met him.
Should it rain, the crops would be saved. = Were it to rain, the crops would be saved.
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，即在从句中be用were代替。
If I were you, I would go to look for him. 如果我是你，就会去找他。
If he were here, everything would be all right. 如果他在这儿，一切都会好的。
典型例题
_____ to do the work, I should do it some other day.
A. If were I B. I were C. Were I D. Was I
答案C. 在虚拟条件状语中如果有were, should, had这三个词，通常将if省略，主语提
虚拟语气在状语从句中的运用除了可以表示条件外，还可以表示比较、结果、目的等。虚拟语气用于表示条件的状语从句中，一般称为虚拟条件句。根据时间的不同，虚拟条件句中谓语动词时态的变化可能有三种形式，即现在、过去和将来。
If it did, it would open up its diversity program, now focused narrowly on race and gender, and look for reporters who differ broadly by outlook, values, education, and class.（2001年 TEXT1）
这是一个含有条件状语从句的复合句。If it did是条件状语从句。主句中主语是it；谓语动词有两个，分别是would open up...和look for...。
这是一个与现在事实相反的虚拟语气，从句用一般过去时，主句用would+动词原形open up和look for。
参考译文：如果它能注意这个问题的话，它就会拓展其雇员多样化项目，而目前的项目只单纯考虑招收不同种族和性别的员工，去雇佣那些在世界观、价值观、教育背景及社会阶层方面各不相同的记者。
二、虚拟语气在名词性从句中的运用
虚拟语气除了用作状语从句中外，还可以用作主语从句、宾语从句、表语从句、同位语从句等名词性从中。
第一，虚拟语气在主语从句中的运用
当it作形式主语，后面用形容词作表语，即在it is + adj.这样的句型中，当描述主语的表语形容词是advisable，critical，crucial，desirable，essential，imperative，important，incredible，inevitable，necessary，recommend，strange，urgent等形容词时，主语从句的谓语动词多用虚拟语气，如果是现在时，谓语动词用should/would +动词原形（should/would经常省略）；如果是过去时，则用should/would + have done的形式。
It was inevitable that this primacy should have narrowed as other countries grew richer. Just as inevitably，the retreat from predominance proved painful.
这是一个含有主语从句的复合句。句首的It是形式主语，真正主语是that从句，该主语从句使用了虚拟语气should+完成时。（2000年 TEXT1）参考译文：随着其他国家日益富裕，美国的这一优势地位逐渐下降是不可避免的。惟其不可避免，从优势地位上退出愈发痛苦不堪。
第二，虚拟语气在宾语从句中的运用
表示“建议、请求、命令、要求”等主观意向的词（如：suggest、advise、assume、decide、demand、desire、insist、propose、order、recommend、require、suggest……），引导宾语从句时需用虚拟语气。虚拟语气中的格式很固定：谓语动词用should+动词原形，should可以省略。注意这种句型中的虚拟语气形式不受主句动词时态的影响。Theories concerning on the individual suggest that children engage in criminal behavior because they were not sufficiently penalized for previous misdeeds or that they have learned criminal behavior through interactions with others.（2004 CLOSE）
此句是个含有一个宾语从句、两个原因状语从句的复合句。suggest是主句谓语，Suggest后面的宾语从句中的谓语动词engage in前面省略了should.
参考译文：关于个体研究的理论认为，孩子们从事犯罪活动是因为以前他们做错事情时对他们的惩罚力度不够，或是因为他们通过与其他人的交往学会了犯罪。
第三，虚拟语气在同位语从句中的运用
名词advice、assumption、decision、demand、desire、insistence、order、proposal、requirement、recommendation、suggestion……后面若有同位语从句，从句的谓语动词也应使用虚拟语气的形式。
Such behaviour is regarded as “all too human”，with the underlying assumption that other animals would not be capable of this finely developed sense of grievance. （2005年 TEXT1）
这是个含有同位语从句的复合句。that引导的同位语从句的谓语动词由would+动词原形be构成。
参考译文：这样的行为被认为“完全是人类独有的特点”，其潜在的含义是其它动物没有这种敏锐的委屈感。
第四，虚拟语气在表语从句中的运用
与同位语从句一样，若主语是某些特定动词的同根名词，要在它后面的表语从句要用虚拟式。
Another decision is whether the school should be one of the vast majority financed by the State or one of the very small but influential minority of private schools，though this choice is，of course，only available to the small number of those who can pay.
这是个含有表语从句的复合句。主语是another decision；谓语是is；whether……or……是表语从句，其中谓语动词由should＋动词原形be构成。参考译文：另一个要做出的决定是：应该选择一所占绝大多数的国立学校呢，还是选择一所数量虽小却有影响力的私立学校呢，当然，只有少数有支付能力的人才有这种选择的权利。
标签：虚拟语气,用法,具体
