2024专升本英语语法基础知识考点：虚拟语气

　　一.虚拟语气在名词性从句中的用法：

　　★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 collegestudent (should) master a foreign language.

　　It is desired that thisrule (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 therewith you.

　　I wish I hadn’t lost thechance.

　　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 onthe earlier train.

　　I’d rather you wenttomorrow.

　　I’d rather you hadn’tdone 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 thatthis (should) be settled as soon as possible.

　　He made the decision thatnothing (should) hold him back.

　　二.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：

　　★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 himyesterday, I should know what to do now.

　　If it had rained lastnight, it might be very cold today.

　　If she were to leave, Iwould 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 betterunder more favourable conditions

　　(= if we had been givenmore favourable conditions).

　　Without your help (= Ifyou 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 youmore help, but he has been so busy.

　　(= if he had not been sobusy).

　　三.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.

　　四.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 ifshe 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 possiblelest 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 everybodymay understand it, write it in simple language.