虚拟语气用来表示说话人的主观愿望或假想,而不表示客观存在的事实,所说的是一个条件,不一定是事实,或与事实相反.虚拟语气通过谓语动词的特殊形式来表示.英语中的语气分为陈述语气、祈使语气、虚拟语气三类.
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.
应用条件
条件状语
If I were you,I would go at once.如果我是你,我马上就会去.（我不可能是你.非真实,虚拟语气,与现在事实相反）
If there were no air,people would die.如果没有空气,人就会死亡.（不可能没有空气.非真实,虚拟语气,与现在事实相反）
2.目的状语
He read the letter carefully in order that he should not miss a word.他把信读得很仔细以便不漏掉一个字.
He started out earlier lest he (should) be late.
他早早的就出发了以防迟到.
3.宾语从句
I insisted that he (should) stay.我坚持要他留下.
He insisted that I (should) go with them.他坚持要我同他们一起去.
4.其他用法
表示想要、宁愿、坚持、命令、建议、要求、、表情绪.观点、与现 在相反的情况、让步状语从句、与客观事实不相符的一种愿望、定语从句、 简单句中、方式状语,看具体情况而言
误区
1.混合条件句的主从句时态不会灵活变化；
2.省略if时,句子调整不正确；
3.不会去找意思中的“应该”含义；
4.陷在虚拟中出不来,把真实条件句当成虚拟条件句.
【典型例题】
1） If I had seen the movie,I ______________ you all about it now.
A.would tell B.will tell C.have told D.would have told
解析：错选D.此题考查混合条件句.从句表对过去的虚拟,主句表对现 在的虚拟,所以正确答案为A.
2）The volleyball match will be put off if it ___.
A.will rain B.rains C.rained D.is rained
解析：答案B.真实条件句主句为将来时,从句用一般现在时.
3）_____ to do the work,I should do it some other day.
A.If were I B.I were C.Were I D.Was I
解析：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,主语提前,变成 were,should,had +主语的形式.但要注意,在虚拟条件状语从句中,省略连词的倒装形式的句首不能用动词的缩略形式.如我们可说 Were I not to do.,而不能说 Weren't I to do.
4).My suggestion is that she ________ more exercise,which will do a lot of
good to her.
A.takes B.must take C.take D.took
解析：错选A.本题要表达“我的建议是她（应该）多锻炼,这对她会有很大好处.”符合虚拟的条件,所以正确答案为C.空前面省略了should.