2015同等学力英语语法之虚拟语气

　　1) 语气：

　　陈述，疑问，祈使，虚拟

　　2) 虚拟语气：表示一种纯然假想的情况或主观愿望，动词需要用一种特殊形式。

　　形式分为三类：现在虚拟语气(动词用原形)，过去虚拟语气(动词用过去式，但动词be要用were)，过去完成形式(动词用过去完成时)。有些情态动词，如should, would, might常用在虚拟语气中。

　　3) 虚拟语气在条件句中的用法：

　　虚拟条件句：就是包含条件从句的句子。

　　条件句分为：

　　真实条件句——有些条件句是可能实现的。

　　虚拟条件句——有些条件句是纯假象的句子。

　　If we leave now, we can still catch the train.

　　If I had enough money, I would buy a computer.

　　If you are waiting for a bus you’d better join the queue.

　　4) 表示现在和将来情况的虚拟条件句：

　　⑴表示现在或将来的虚拟条件句——从句中的谓语(用过去式形式);主句谓语(would+动词原形)

　　If I had a map I would lend it to you.

　　If you left your bike outside, someone would steal it.

　　If I were you I’d plant some trees round the house.

　　注：If I were you句中，were不能改成was,但在第三人称单数后用was也可以。如：

　　If Helen were(was) here how nice it would be!

　　⑵主句谓语有时也可以由might, could构成。

　　If I could type, I might save a lot of time.

　　If he had a permit he could get a job.

　　⑶在条件句从句中有时还可以用were to +动词，或should+动词。

　　If he were (was) to resign, who would take his place?

　　If I should be free tomorrow, I will come to see you.

　　⑷在某些条件从句中(如were to +动词，should+动词)，if有时可以省略，这时语序要改为倒装。

　　Were I Tom, I would refuse.

　　Were I in your shoes I would let him know what I thought of him.

　　Should she be interested, I’ll phone her.

　　⑸从句有时可以用If it were not for这种句型，表示“若不是”。

　　If it were not for your help, we would be in serious trouble.

　　表示过去情况的虚拟条件句：(这类从句表示一个与事实相反的过去情况)

　　⑴表示过去情况的虚拟条件句——条件从句中的谓语(相当于过去式的形式);主句的谓语(would have+过去分词)

　　If I had known that you were coming, I would have met you at the airport.

　　If I had left sooner, I’d have caught the bus.

　　What would you have done if you’d been in my position?

　　注：在主句中，如果主语是第一人称，可以用should构成谓语。

　　I should (would) have talked it to my mother if I had thought of it.

　　⑵主句中也可用could和might构成，有时还可由should构成。

　　If my father had lived, he could have done all this for me.

　　If we had found him earlier we might have saved his life.

　　If he had apologized, you should have done so too.

　　⑶从句中也可用had not been for来构成谓语，表示“要不是”。

　　If it hadn’t been for your timely help, we would have got into serious trouble.

　　If it hadn’t been for her meticulous care, I wouldn’t have got well so soon.

　　⑷if有时可以省略，但后面部分需要倒装。

　　Had I not seen it with my own eyes, I would not have believed it.

　　Had it not been for their support, we couldn’t have won the election.

　　Had Mark been in charge, it wouldn’t have happened.

　　其他知识点：

　　1) 常考点有：对a、过去的虚拟语气，b、错综句的考查，c、还有去掉if将助动词had ，情态动词should，be动词提前等

　　2) 要注意哪些词可以用作虚拟语气 如as if(though)，if only, demand, insist, suggest但要注意suggest 表示“表明”时不用虚拟语气,如 her expression suggest that she made a mistake.

　　3) 要求，建议，命令等+ (should) do，用虚拟语气demand, insist, require，request, demand, desire, ask(要求),suggest，advise, propose(提议)，urge(催促)，vote(投票)，command(命令), order, recommend，intend, petition(恳请)。

　　4) It is adj. that… 用虚拟语气 important, illegal, essential，vital，appropriate，unfair，dreadful，strange，surprising，natural，unthinkable

　　5) It’s (high) time后的定语从句中谓语要用虚拟语气(多用过去虚拟语气)

　　It’s high time we went.

　　6) 错综时间条件句：有些条件句主句谓语和从句谓语表示的动作在时间上并不一致。

　　If the weather had been more favorable, the corps would be growing still better.

　　If he had received six more votes, he would be our chairman now.

本文选自新东方在线论坛。