虚拟语气
定义：虚拟语气用来表示说话人的主观愿望或假想，不是事实或与事实相反。
陈述语气
祈使语气
动词的语气非真实条件句中的虚拟语气
名词性从句中的虚拟语气
虚拟语气特殊句型中的虚拟语气
虚拟语气需特别注意的情况
用法：
一．IF引导的虚拟句式
注意；混合虚拟
（1）不同时间的虚拟：
If he had listened to me, he would not be in trouble now.
If he had told me yesterday, I should know what to do now.
(2) 虚拟与陈述的混合：
He could have passed the exam, but he wasn’t careful enough. You should have come earlier, the bus left a moment ago.
二．名词性从句中的虚拟语气:从句谓语动词(should) +do
1.主语从句：it is + adj + that结构
2.宾语从句：主语+要求接虚拟语气的动词+that
一个坚持：insist
两个命令：order; command 两个决定：decide; determine
三个建议：suggest; advise; propose
四个要求：demand; ask; request; require
注意：① suggest：暗示；insist：坚持说(不虚拟)
② except, believe, think suspect等动词的否定形式或疑问句后面的宾语从句要用虚拟。
I never thought that he should be such a brave young solider
③ should竟然
I am glad that your novel should have won the first prize.
④ wish引导从句的虚拟语气，谓语动词变化和if从句虚拟语气一样。
Wish可以用以下结构：wish +主语+would/should have done
3.表语从句、同位语从句
三、其他用法
一、名词性从句的虚拟语气中，表示建议、命令、要求的含义是，无论主句谓语动词为何种时态，从句的谓语动词都用："should + do"。
should可以省略。
但是：
insist意为“坚持某种动作”才用虚拟语气；意为“坚持某种观点，某个事实”则不用虚拟语气。
He insists he is a student. 他坚持说他是个学生(表示的是事实，因此在这个语句中不能使用虚拟语气)
suggest意为“建议”才用虚拟语气，意为“暗示”则不用虚拟语气。
His face suggests that he looks worried.
他的表情暗含着他很担心(本身是事实，因此它就没有用到虚拟语气)
二、even if, even though 所引导的让步状语从句中
与现在事实相反：从句may/might+动词原形，may/might可以省略，
与过去事实相反：从句had done
类似的词有though/even though/whatever/however/so long as;
主、从句的结构与if所引导的条件从句结构相同
Even if he were here himself, he should not know what to do.
即使他亲自来也不知该怎么办。
（事实：他没来）
Nobody could save him even though Hua Tuo should come here.
即使华佗在世也救不了他。
（事实：华佗不在世）
三、含蓄的虚拟语气：but/but for, or，in that case, without, otherwise,
四、would rather, had rather, would sooner等后的宾语从句常表示与客观事实不符的一种愿望，其虚拟语气结构为：
过去 had + done I'd rather you had seen the film yesterday. 我倒想你昨天看过了这场电影。
现在 did/were I'd rather you were here now. 我倒想你现在在这儿。
将来 did/were We'd rather you went here tomorrow. 我们倒想你明天去那儿
五、wish 后宾语从句
1、表示与现在事实相反的愿望，谓语动词：did/were
I wish I had your brains. 我希望我有你那样的头脑。
(事实：我根本比不上你)
2、表示与过去事实相反的愿望，谓语动词：had + done
I wish I had known the truth of the matter.
我希望我那时就知道这件事情的真相。
（事实：那时还不知道）
3、表示将来难以实现的愿望。
谓语动词： would /could / should / might + 动词原形
I wish I should have a chance again.
我希望我还能有一次这样的机会。
（事实：很难再有这样的机会了）
(if only引导的感叹句和as if/as though引导的状语从句也有相同用法)
if only…若是…该多好啊；真希望…
与现在事实相反，从句谓语：did / were
与过去事实相反，从句谓语：had
done If only she had lived a little longer.
cou ld have done If only she could have lived a little longer.
将来可能性不大，从句谓语：would /could / should / might +do
as if, as though有时候引导虚拟语气
与现在事实相反，从句谓语动词：did / were
与过去事实相反，从句谓语动词：had done
将来可能性不大，从句谓语动词：would /could / should / might +do
六、目的状语从句
1、在for fear that, in case, lest引导的从句中，若用虚拟语气时，从句谓语为：（should ）+ do。
She examined the door again for fear that a thief (should) come in.
她又把门检查了一遍，以防盗贼的进入。
He started out earlier lest he (should) be late. 他早早的就出发了以防迟到。
2、so that, in order that所引导目的状语从句中，
从句中谓语为：can / could / may / might / will / would / should + do
He goes closer to the speaker so that he can hear him clearer.
他走近说话的人以便能听得更清楚。
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。
七、虚拟语气还可用在定语从句中，表示：“早该做某事了”时，谓语动词须用虚拟语气，从句虚拟语气结构：
It is (high / about) time that + 主语 + 动词的过去式
should + do（should不可省，且优先使用动词过去式）
It is time for sb. to do sth.
It is time that I went to pick up my daughter at school. 我该去学校接我的女儿了。
It is high time you should go to work. 你早该上班了。
It is （the first / second / third…）time that 从句谓语动词用have done
It was（the first / second / third…）time that 从句谓语动词用had done
八、固定搭配
1. Were it not for…“要不是……”与现在事实相反：
Were it not for your help, I would never be a good boss.
2. Had it not been for…“当时要不是”与过去事实相反：
Had it not been for you, I would have lost my way.
3. What if “要是…该怎么办？”if从句谓语用should
do:
What if it should rain heavily tomorrow?
4. Would you mind + if “你介不介意，如果……”从句谓语多用did:
Would you mind if I opened the window?
辨别would，could，should，might
Would 必然的结果
Could 能够
Might 可能的结果
Should 在主句中，它的主语只能是第一人称I或we。