（一）动词wish后的宾语从句用虚拟语式
动词wish后的宾语从句用虚拟语式，与现在事实相反，用were或动词的一般过去式；与过去事实相反，用had+过去分词或would /could+have +过去分词；表示将来没有把握或不太可能实现的愿望，用would / should (could, might)＋动词原形。例如：
I wish she were here.
I wish she had taken my advice.
I wish you would go with us tomorrow.
A:“ You have made some mistakes.”
B:“ I wish I didn't make mistakes every day.”
A:“What would you wish to do if you were a college student again?”
B:“ That's very hard to say, but I wish I had studied psychology.”
Note:
比较下面几个表示未实现的愿望的句子：
I should like to have taken his advice.
我现在真希望（那时）采纳了他的建议。
I should have liked to take his advice.
我本希望采纳他的建议的。
I should have liked to have taken his advice.
（意同上面第二句，但结构笨重）
（二）if only 和would that 后用虚拟语式
if only 和would that 后用虚拟语式，谓语动词用一般过去时表示现在没有实现的愿望，用过去完成时表示过去没有实现的愿望，常译为“要是…就好了”。例如：
If only she had known where to find you.
If only I could speak several foreign languages!
Would that I were young again.
would that 实际上是I (we) would的简化，I would相当于I wish.例如：
I would I were a bird and could fly freely in the sky.
We would that we had seen through him earlier.
Note:
O that 和 Would to God是would that的变体。例如：
O that money grew on the trees.钱长在树上就好了。
Would to God she would return safely.但愿她平安归来！
（三）在suggest, order, demand等后要用虚拟语式
在propose, command, request, desire, insist, require, decide, promise, arrange, ask, move, consent, determine, recommend, advise, intend, beg, resolve, argue, maintain, deserve, prefer, decree, vote, urge, instruct, advocate, persuade, dictate, legislate, sentence, object, expect, direct, appoint, provide, specify, persist, permit等意念动词、祈使动词或态度动词后的宾语从句中，要用虚拟语式，这时，谓语动词用动词原形或should+动词原形。例如：
He determined that she (would) go at once.
They intended that the news (should) be suppressed.
I prefer that you not eat the meat.
She insisted that the seats (should) be booked in advance.
The workers demanded that their wages (should) be raised by 10 percent.
They requested that the (should) sing a song.
He advised that the doctor (should) be sent for.
The committee decided that no one should be admitted without a ticket.
Sometimes she would suggest that I should be saving some of the money.
The examination instructions ask that the students (should) not use a red pen.
It was arranged that she leave the next week.
Note:
When he was asked why his friend had not accepted the offer, he suggested that his friend's pride prevented him from accepting.
句中suggested不作“建议”解，而是作“暗示”解，故用陈述语式。如果上述动词作其他意思解释，或者说话者认为所讲的事是事实，要用陈述语式。比如，当suggest作“暗示、表明”解， insist不表示“坚决要求”，而作“坚决认为”解，其后的从句要用陈述语式，不用虚拟语式。再如：
He insisted that he was not involved in the case.
When asked why he declined our invitation, he suggested that he was not on good terms with the director.
（四）在advice, demand, order等名词后要用虚拟语式
在advice, demand, order等名词后的主语从句和表语从句中用虚拟语式。常用的这类名词有：advice, demand, order, necessity, resolution, pay, decision, proposal, requirement, suggestion, idea, recommendation, preference, request, plan, motion等。这时，谓语用动词原形或should+动词原形。例如：
The demand is that manuscripts (should) be written on one side only.
He issued the order that the troops (should) withdraw at once.
（五）在important, necessary等后用虚拟语式
形容词important, necessary, imperative, natural, urgent, essential, appropriate, desirable, insistent, obligatory, probable, vital, advisable, better, keen, preferable, possible, incredible, funny, concerned, ridiculous, unthinkable, 以及短语no wonder, a pity, not right等可以构成“it is +形容词（名词）+that”句型，其后的句子要用虚拟语式，为(should) be型。例如：
It is necessary that some immediate effort (should) be made.
必须立即采取行动。
It is essential that the program (should) be loaded into computer.
把程序输进计算机非常必要。
Note:
It is amazing (odd, strange, surprising, wrong, astonishing, inconceivable, a pity, a shame, a thousand pities, to be regretted)、 I am surprised (sorry) 和I regret等结构后的that 从句中要用should，意为“竟然”，表示说话人的惊异、懊悔、失望等情感。例如：
It is amazing that he should have learnt so much in such a short time.
I am surprised that he should have been so rude to you.
I regret that I should have forgotten to tell you the fact.
It is a pity that Henry should be so careless.
It is a shame that he should have done such a thing.
有时候，可以将表示情感等的句子前一部分省略，只保留that 以后的部分，成为虚拟式的感叹句。例如：
That he should miss such a golden opportunity! (= It is a pity that…)
That they should resort to violence! (= I am surprised that…)
（六）It is (high, about) time…句型用虚拟语式
It is (high, about) time…句型要求用虚拟语式，谓语动词用过去式，指现在或将来的情况，表示“早该干某事而已经有些晚了”。例如：
It is time that we went to bed.
It is time that somebody taught you to behave yourself.
这种结构中的过去式也可改为should+ 动词原形（用should时，不能将其省略），但不如用过去式普通。例如：
It is about time we should go to bed.
It is time she should wash her clothes.
I suppose it's almo
