虚拟语气是一种动词形式，表示说话人的一种愿望，假设，怀疑，猜测，建议等含义，虚拟语气所表示的含义不是客观存在的事实。
 
 If I were you, I’d take them away. 如果我是你的话，我就会带走他们。
 
 If I had met Li Hua, I could had told him. 如果我碰见了李华，我就告诉他了。
 
 If I had time. I could come to help you. 如果我有时间，我会来帮助你的。
 
 He suggested that our class should be divided into five groups. 他建议说我们的班应该分成五个小组。
 
 He speaks to us as if he had been there. 他给我们讲的好象他去过那儿。
 
 虚拟语气的用法：
 
 一. 虚拟语气用在简单句中，表示祝愿，命令。
 
 May you be happy. 祝你幸福。
 
 May you have a good time. 祝愿你玩的痛快。
 
 May the friendship between us last long. 祝愿我们的友情天长地久。
 
 Have a good journey! 祝愿你旅途愉快！
 
 You go out！ 你出去！
 
 二. 虚拟语气用在宾语从句中。
 
 动词 suggest, order, insist, propose, require, request, recommend, command, desire,等词后面的宾语从句表示的是一种虚拟语气，宾语从句中的动词动作表示的只是一种愿望、要求。
 
 He insisted that all of us should be there on time by any means.
 
 他坚持要我们大家想尽办法按时去那儿。
 
 动词 demand, suggest, order, insist, propose, require, request, recommend, command, desire,等后面的从句中，"should" 可以省略。
 
 The teacher suggested that we (should) clean the blackboard after class.
 
 老师建议我们课后把黑板擦了。
 
 He ordered that the students wash the clothes every week by themselves.
 
 他要求学生每周都要自己洗衣服。
 
 He asked that he be given an opportunity to try.
 
 他要求给他一个试试的机会。 三. 虚拟语气用在主语从句中。
 
 在句型 "It is important (necessary, strange, natural，desired, requested, ordered, 等) that .... " 中，that 后面的从句中的谓语动词用： should + 动词原形
 
 It’s necessary that we should have a walk now.
 
 我们有必要出去散散步。
 
 It’s natural that she should do so. 她这样做是很自然的。
 
 It’s important that we should take good care of the patient.
 
 重要的是我们要照顾好病人。
 
 It is desired that we (should) get everything ready by tonight.
 
 四. 虚拟语气在表语从句和同位语从句中。
 
 suggestion, motion, proposal, order, recommendation, plan, idea, 等后面的表语从句和同位语从句。
 
 My suggestion is that we (should) send a few people to help the other group.
 
 我的建议是我们派几个人去帮相别的小组。
 
 His sole requirement is (was) that the system be adjusted.
 
 他唯一的要求是把这个体系做些调整。
 
 The orders were that we stay where we were.
 
 命令是我们仍留在原处。