虚拟语气：虚拟证据表示说的话不是事实，或者不可能发生的情况，而是一种愿望、建议或者与事实相反的假设等，一般常用于正式的书面语中。
一、虚拟语气在if条件从句中的用法：
1、a. If I were you, I would apply for the job.
b. If I lived near my office, I would walk to the office.
与现在事实相反，If条件从句谓语：过去式（be用were）
主句谓语：should / would / could / might+动词原形
2、a. If you had been more careful, You could have passed the exam.
b. If you had turned off the gas, the house wouldn’t have caught fire.
与过去事实相反，If条件从句谓语：had+动词过去分词
主句谓语：should / would / could / might + have done
3、a. If it should rain tomorrow, we would not go camping.
b. if it were to rain tomorrow, we would not go camping.
c. If it rained tomorrow, we would not go camping.
与将来事实相反：If条件从句谓语：过去式/ should + v原形/ were + to do
主句谓语：should / would / could / might + do
二、混合虚拟条件句：不同时间的虚拟，各遵守各的规则，如：
a. If you had followed the doctor’s advice, you would be quite all right now.
从句叙述与过去事实相反（had + done），主句叙述与现在事实相反（would + v）
b. If I were you, I would have taken his advice.
从句叙述与现在事实相反（过去式），主句叙述与过去事实相反（would have done）
三、虚拟语气在宾语从句中的适用：
a. They demanded that the black people (should) be treated as well as white people.
b. He suggested that we (should) start off at once.（建议）
His smile suggested that he was satisfied with our work.（暗示，表明）
c. I insisted that you (should) give me my money back.（坚决（持），要求）
Mike insisted that he had never stolen anything.（坚持说/坚持认为）
这类动词有：一坚持（insist），二命令（order, command），三建议（advise, suggest, recommend, propose），四要求（require, request, demand, desire）
d. I wish I were a bird.
I do wish you would come earlier next time.
I wish I had done better in my work.
四、虚拟语气在主语从句中的适用：
1. It was / is important / vital / necessary / appropriate / proper / right that……
eg: It is important that we (should) think before we decide.
2. It is important that we (should) think before we decide.
据建议/要求/命令……
eg: It is suggested that parents (should) spend more time with their children alone.
五、虚拟语气在表语从句中的适用（与表示决定、主张、要求、建议、命令的名词。如：suggestion,
proposal, advice, order, demand, requirement等）构成的表语从句常用should + do结构eg：Our suggestion is that the meeting (should) be put off.
六、虚拟语气在同位语从句中的适用（与表示决定、主张、要求、建议、命令的名词。如：
suggestion, proposal, advice, order, demand, requirement等）构成的同位语从句中常用should + do结构
eg: Doctors give us some advice that we (should) pay more attention to our health.
七、含蓄条件句的虚拟语气：由but for（要不是），Without（要是没有），otherwise（要不然）,but
等引导
如：but for the storm, I would have arrived much earlier.
Without your help, I wouldn’t have passed the driving test.
I was too busy at that time. Otherwise I would have called you.
I would have come to see you, but I was too busy.
注意：句子或主句中的谓语动词的形式视具体情况而定。这是考查考生应变能力的最佳试题。
八、虚拟语气的其他用法
1、It’s (high) time that 从句: (从句用过去式或者should + 动词原形
eg：It’s high time that you went to school.
2、If only（要是……就好了……）用一般过去式表示与现在或将来事实相反，用过去完
成的表示与过去事实相反。
eg：If only I were a film star.
If only I had known his phone unmber.
3、as if引导的方式状语从句中的虚拟语气：
eg: He treats me as if I were his own son.
