虚拟语气
1. 表示目前/过去/以后状况的虚拟条件句
虚拟条件句主要有三种结构：
1)表示与目前状况相反：主句谓语用“would / could / might +动词原形”，从句谓语用“动词的一般过去时”。
If I were you, I would not accept his offer.
If I had time, I would certainly go to the cinema with you.
2) 表示与过去状况相反：主句谓语用“would / could / might + have +过去分词”，从句谓语用过去完成时。
If I had got up a little earlier, I wouldn’t have missed the train.
If I had been more careful, I might have passed that exam.
3) 表示与以后状况相反：主句谓语用“would / could / might +动词原形”，从句谓语用“were +动词不定式”或“should +动词原形”。
If I were to do the job, I would not be able to have enough time to study.
If it should rain tomorrow, I would not go out with you.
2. 虚拟条件句连接词if的省略
假如虚拟条件句的从句中含有were, had, should, could等词时，可以省略连接词if，但这个时候需要把were, had, should, could等词移到主语前面，形成倒装。这种句型主要用于书面形式。
Were I to do the job, I would finish doing it within two weeks.
Had it not been for his help, we couldn’t have arrived there on time.
Should it rain tomorrow, I would stay at home.
3. wish后宾语从句中的谓语构成
动词wish后的宾语从句表示未达成的或不可能达成的愿望，其宾语从句中的谓语动词要用虚拟语气，有以下三种构成形式。
1) 表示目前不可能达成的愿望，宾语从句中的谓语动词用一般过去时。。
I wish I had enough money to buy a car.
I wish I were as young and energetic as you.
2) 表示过去未能达成的愿望，宾语从句中的谓语动词用过去完成时或“would / could + have +过去分词 ”。
I wish I hadn’t made such a mistake.
I wish I could have done it better.
3) 表示以后不可能达成的愿望，宾语从句中的谓语动词用“would / should +动词原形”。
I wish I would not get old.
I wish I could travel around the world one day.
4. 某些动词后的宾语从句中谓语动词要用虚拟语气
在一些动词后面的宾语从句中，谓语动词要用虚拟语气。这个时候，谓语动词用动词原形或should +动词原形。这种动词一般表示命令，需要，决定，建议，倡导等定义，主要有：advise, ask, command, decide, demand, desire, direct, insist, move, order, propose, recommend, request, require, suggest,等。
The workers demanded that their wages be raised by 10 per cent.
The teacher decided that you do the experiment first.
5. 某些名词后的表语从句和同位语从句中谓语动词要用虚拟语气
在一些名词后面的表语从句和同位语从句中，谓语动词要用虚拟语气。这个时候，谓语动词用动词原形或should +动词原形。这种名词一般表示命令，需要，决定，建议，倡导等定义，主要有：advice, idea, instruction, motion, order, plan, proposal, recommendation, request, requirement, suggestion,等。
My suggestion is that we send for a doctor immediately.
He gave the order that they do the experiment again.
6. 错综时间条件句
条件从句表示的动作和主句表示的动作，有时发生的时间是不同的.如从句是对过去状况的假设，而主句可能是对目前正在进行状况的假设。这种句子称为错综时间条件句.
If the weather had been more favourable, the crops would be growing still better.
虚拟条件句的倒装
虚拟条件句的从句部分假如含有were, should, 或had, 可将if省略，再把were, should或had 移到从句句首，实行倒装。
1. Were they here now, they could help us.
=If they were here now, they could help us.
2. Had you come earlier, you would have met him
=If you had come earlier, you would have met him.
3. Should it rain, the crops would be saved.
=Were it to rain, the crops would be saved.
注意：
在虚拟语气的从句中，动词'be'的过去时态一律用"were"，不需要was， 即在从句中be用were代替。
1. If I were you, I would go to look for him.
假如我是你，就会去找他。
2. If he were here, everything would be all right.
假如他在这儿，所有都会好的。
典型例题
_____ to do the work, I should do it some other day.
A. If were I B. I wereC. Were ID. Was I
答案C. 在虚拟条件状语中假如有were, should, had这三个词，一般将if省略，主语提前, 变成 were, should, had +主语的形式。但应该注意，在虚拟条件状语从句中，省略连词的倒装形式的句首不可以用动词的缩略形式。如大家可说 Were I not to do., 而不可以说 Weren't I to do.
特殊的虚拟语气词should
1. 以下几类结构中的主语从句的谓语动词要用should 加动词原形， should 可省略。
It's suggested/ ordered/ proposed/ required/demanded/ requested/ insisted/ necessary + do
It's important/ necessary/ natural/ strange
It's a pity/a shame/no wonder
2. 在宾语从句中的应用
在表示命令、建议、需要等一类动词后面的从句中。order, suggest, propose, require, demand, request, insist, command, insist + do
e.g. 1) I suggest that we hold a meeting next week.
2) He insisted that he be sent there.
注意：如suggest, insist不表示"建议" 或"坚持要某人做某事时"，即它们用于其本意"暗示、表明"、"坚持觉得"时，宾语从句用陈述语气。
e.g. The guard at gate insisted that everybody obey the rules.
判断改错:
1) You pale face suggests that you be ill.
2) Your pale face suggests that you are ill.
3) I insisted that you be wrong.
4) I insisted that you were wrong.
（1，3错；2，4对）
3. 在表语从句，同位语从句中的应用
在suggestion, proposal, idea, plan, order, advice等名词后面的表语从句、同位语从句中要用虚拟语气，即+动词原形。
e.g. 1) My idea is that we get more people to attend the conference.
2) I make a proposal that we hold a meeting next week.
全部倒装
全部倒装是指将句子中的谓语动词全部置于主语之前。此结构一般只用与一般目前时和一般过去时。容易见到的结构有：
1. here, there, now, then, thus等副词置于句首, 谓语动词常用be, come, go, lie, run。
e.g. 1) There goes the bell.
2) Then came the chairman.
3) Here is your letter.
2. 表示运动方向的副词或地址状语置于句首，谓语表示运动的动词。
e.g. 1) Out rushed a missile from under the bomber.
2) Ahead sat an old woman.
注意：上述全部倒装的句型结构的主语需要是名词，假如主语是人称代词则不可以完全倒装。
e.g. 1) Here he comes.
2) Away they went.
