英语中的虚拟语气
虚拟语气是说话者用来表示假设，或难以实现的情况，而非客观存在的事实，所陈述的是一个条件，不一定是事实，甚至完全与事实相反。此外如需表达主观愿望或某种强烈的感情时，也可用虚拟语气。虚拟语气通过谓语动词的特殊形式来表示。
中文名: 虚拟语气
外文名: Subjunctive Mood
意义: 说话人的主观愿望或非真实情况，而不表示客观存在的事实。虚拟语气是由句中的谓语动词的特殊形式表示出来的。如：
If I were a bird，I would be able to fly in the air.
如果我是一只小鸟，我就能在空中飞行。
I wish I could pass the examination.
我希望我能通过考试。
在表示假想的虚假的、与事实相反的或难以实现的情况时用虚拟语气，表示主观愿望或某种强烈情感时，也用虚拟语气。即当一个人说话时欲强调其所说的话是基于自己的主观想法，愿望，假想，猜测，怀疑或建议，而不是根据客观实际，就用虚拟语气。
虚拟语气有三种基本结构，分别是：对过去的虚拟，对现在的虚拟和对将来的虚拟
用固定的情态动词表示的虚拟语气
1. should (1)用在动词如advise, command, demand, desire, insist, order, propose, recommend, request, require, suggest, urge等后的宾语从句中。例如：
1) They requested that we (should) send a delegation to their country.
2) She urged that he write and accept the post.
(2)用在it is suggested, it is desired, it is required, it was ordered, it was proposed, it has been decided, it is necessary (essential, imperative, important, desirable) that等引出的主语从句中。例如：
1) It is desired that we (should) get everything ready by tonight.
2) It is necessary that the teacher (should) have a thorough knowledge of the subject he teaches.
(3)用在suggestion, motion, proposal, order, recommendation, plan, idea, requirement 等引起的表语从句和同位语从句
例如：He put his coat over the child lest he should catch cold.
2.用在表示比拟的方式状语从句中
例如：They talked as if they had been friends for years.
3.用在表示虚拟情况的定语从句中
例如：It is high time you handed in your test paper.
4.用在某些表示主观愿望的名词从句中
例1：I wish I were as strong as you.
例2：He insisted that we (should) take up the matter at the meeting.
5.用在婉转的请求、建议、批评等句子中
例1：Could you spare me a few minutes?
例2：You might have told me earlier.
例3：Hadn’t you better go and see you dentist about that tooth?
6.用在表示祝愿的简单句中
例1：Long live world peace.
例2：May you succeed.
