★在“It is / was +形容词或过去分词+ that从句”结构的主语从句中，表示命令、愿望、建议等，谓语动词为“should +动词原形”，should也可省略。 如： It is necessary that a college student (should) master a foreign language.
It is desired that this rule (should) be brought to the attention of the staff.
★动词wish后的宾语从句中，表示与现在事实相反时，从句中动词用过去式；表示与过去事实相反时，从句中动词用“had +过去分词”；表示将来很难实现的愿望时，从句中动词用“would / could / might +动词原形”。如：
How I wish I was there with you.
I wish I hadn’t lost the chance.
I wish he would / could / might go with us to the theatre.
★在would sooner, would rather等后面的宾语从句中动词要用虚拟语气。尚未发生的动作用动词的过去式，已经发生的动作用“had +过去分词”。如：
I would sooner he left on the earlier train.
I’d rather you went tomorrow.
I’d rather you hadn’t done that. ★表示“建议、命令、要求、坚决做”等动词（如suggest, demand, require, request, order, insist等）后的宾语从句中谓语常用“（should +）动词原形”。如：
I suggest you (should) have enough sleep.
I recommend that everyone (should) attend the party.
★虚拟语气还可用在表示愿望、建议、命令、请求等的表语从句或同位语从句中，谓语用“should +动词原形”，should也可省略。如：
Our only request is that this (should) be settled as soon as possible.
He made the decision that nothing (should) hold him back. 2. 虚拟语气在条件句中的用法 ★虚拟语气在if条件状语从句中的用法：
条件句 从句中谓语的形式 主句中谓语的形式 表示现在情况 动词过去式（be的过去式用were） should / would / might / could +动词原形 条件句 从句中谓语的形式 主句中谓语的形式 表示将来情况 should +动词原形；were to +动词原形；动词过去式（be的过去式用were） should / would / might / could +动词原形 表示过去情况 had +过去分词 should / would / might / could + have +过去分词 ★在错综时间虚拟条件句（即主句和从句所指的时间不一致）中，动词的形式需要根据表示的时间来调整。如：
If I had spoken to him yesterday, I should know what to do now.
If it had rained last night, it might be very cold today.
If she were to leave, I would have heard about it.
★含蓄条件句
有时虚拟语气的条件并不是直接通过条件句来表示，而是用一些词或短语（如under, with, without, but for等）或上下文暗示来说明。句中的虚拟语气一般表示过去的情况，这种句子叫含蓄条件句。如： We could have done better under more favourable conditions (= if we had been given more favourable conditions).
Without your help (= If you hadn’t helped me), I couldn’t have succeeded.
But for the heavy traffic (= If the traffic had not been so heavy), we would have arrived earlier.
He would have given you more help, but he has been so busy (= if he had not been so busy).
3. 虚拟语气中if的省略 如果条件从句的谓语中有were, had或should等词，可将if省略，而把这几个词放在句首，其意义与带有if的条件句相同。如： If I were to do the work, I should do it some other way. → Were I to do the work, I should do it some other way.
4.虚拟语气在其它状语从句中的用法
★在由as if或as though引导的方式状语中，虚拟语气的形式为动词的过去式（be用were）或“had +过去分词”。如：
She is walking slowly as if she were tired. ★在由lest, for fear that, in case等引导的从句中，虚拟语气的形式为“should +动词原形”。如：
I ran as fast as possible lest I should be too late.
★在由in order that, so that或that引导的目的状语从句中，虚拟语气的形式为“may / might / could +动词原形”。如：
In order that everybody may understand it, write it in simple language.
1. 在if条件句中的用法 Sorry, I am too busy now. If I _____ time, I would certainly go for an outing with you.
A. have had B. had had C. have D. had
D 2. 特殊用法 Had they known what was coming next, they _____ second thoughts. A. may have B. could have C. must have had D. might have had
由Had they known可知，虚拟条件从句中省略了if，将had提前。从句与过去事实相反，所以主句谓语用“should / would / could / might + have +过去分词”。
D 3. 虚拟语气在定语从句中的运用 Jack is a great talker. It’s high time that he _____ something instead of just talking.
A. will do B. has done C. do D. did
4. 虚拟语气在名词性从句中的运用 —Where are the children? The dinner’s
going to be completely ruined. —I wish they _____ always late.
A. weren’t B. hadn’t been C. wouldn’t be D. wouldn’t have been D A
5. 虚拟语气在as if / though引导的从句中的运用 Don’t handle the vase as if it _____ made of steel.
A. is B. were C. has been D. had been B
从A、B、C、D四个选项中，选出可以填 入空白处的最佳选项。 1. We would rather our daughter _____ at home with us, but it is her choice, and she is not a child any longer.
A. would stay B. has stayed
C. stayed D. stay C 2. _____ the morning train, he would not have been late for the meeting.
A. Did he catch B. Should he catch
C. Has he caught D. Had he caught 3. People are recycling many things which they _____ away in the past.
A. had thrown
B. will be throwing
C. were throwing
D. would have thrown D D 5. If Mr. Dewey _____ present, he would have offered any possible assistance to the people there.
A. were
B. had been
C. should be
D. was 5. We _____ back in the hotel now if you didn’t lose the map.
A. are B. were
C. will be D. would be B D 6. _____ no modern telecommunications, we would have to wait for weeks to get news from around the world.
A. Were there B. Had there been
C. If there are D. If there have been 7. It was John who broke the window. Why are you talking to me as if I _____ it?
A. had done B. have done
C. did D. am doing A A 8. They were abroad during the months when we were carrying out the investigation, or they _____ to our help.
A. would have come B. could come
C. have come D. had come A