假设语气

直述句：

If you are free, please help me with my homework. 表“有帮忙的可能性” 假设句：

If I were free, I would help you with your homework 表“我现在没空，所以无法帮助你”

一. 假设法现在式

表示现在未来不确定的假设

If + 主词 + 现在式动词/动词原形, 主词 + will/shall + 动词原形 If it is rains tomorrow, we will cancel the picnic. 重点1：

下列两种情况，可用假设法现在式

1>主词+动词(suggest, demand, insist, agree…) + that + 假设法现在式 I suggest that everyone (should) help in some way.

I insist(坚持) that she (should) consult(请教) the doctor. 2>It is 形容词(necessary, important…) + that + 假设法现在式 It is important that she (should) be honest.

二．假设法过去式

(表示与现在事实相反的假设)

If + 主词 + were/过去式动词/过去式助动词, 主词 + would/could/should/might + 动词原形 If I were young, I could enjoy this party. Truth=> As I am not young, I cannot enjoy the party.

If I had a lot of money, I would buy a car. Truth=> As I am don’t have a lot of money, I won’t by a car.

三. 假设法过去完成式

(表示与过去事实相反的假设)

If + 主词 + 过去完成式(had + p.p.)…,主词 + would/could/should/might + have p.p….

If I had known the gossip, I would have told you. Truth=> As I didn’t know the gossip, I wouldn’t tell you.

We would not have dozed off if our teacher had spoken louder. Truth=> We dozed off as our teacher didn’t speak loud. 重点1:

在条件句子中,除了if之外,也可以用suppose(supposing), suppose(that), providing(provided), provide that, as(=so) long as, in case, unless… Suppose(supposing) you had ten million dollars, what would you like to do first?

I will stay here provided(providing) the climate(气候) agree with me tomorrow. 重点2:

假设过去试和假设过去完成式混用.

If I had done my homework, I would go on a date with her now.

Truth=> As I didn’t do my homework, I don’t go on a date with her now. 四. 假设法未来式

If + 主词 should(万一)/were to + 动词原形…, 主词 + would(will…) + 动词原形 If it should rains, the game would(will) be put off . =>明天有下雨的可能性

If the Pacific ocean(太平洋) were to dry up, I would change my mind. =>决不会改变心意 重点1:

假设句中,也可以省略if, 形成Were(Had/Should…) + 主词的顺序 If I were a bird, I could fly to you. => Were I a bird, I could fly to you.

If he had known the truth, he would have told you. =>Had he known the truth, he would have told you. If it should rain, I would stay at home. =>Should it rain, I would stay at home. 五. 其它假设法的表现

1> …as if/as though(仿佛,好像) + 主词 + 假设过去式/假设过去完成式 He talks as if(as though) he knew the everything. She looks as if(as though) she has seen the ghost. He laughs as if(as though) nothing had happened.

2> …wish(希望) + S + 假设法过去式/假设法过去完成式 I wish I knew Annie’s cell phone number.

=>I’m sorry I don’t know Annie’s cell phone number. I wish I hadn’t bought such an expensive dress. =>I’m sorry I bought such an expensive dress.

3> It’s time/about time/almost/high time + (that) + S + 假设法过去式 It’s time pass midnight. It’s time (that) the children went to bed. =>It’s time (that) the children went to bed. =>It’s time for children to go to bed.

It’s a about time you apologized to her for what you did.

4> If only(只要,要是…多好,但愿) + 主词 + 假设法过去式/假设法过去完成式

If only my tooth would stop hurting! If only I had taken his advice.

注意: if only和I wish表现上意思差不多

5>If it were not for…=>假设法过去式(若没有的话)

If it had not been for…=>假设法过去完成式(若没有的话) If it were not for music, he couldn’t live a moment. =>Were it not for music, he couldn’t live a moment. =>Without music, he couldn’t live a moment. =>But for music, he couldn’t live a moment.

If it had not been for the traffic jam, we would have been in time for the game. =>Had it not been for the traffic jam, we could have been in time for the game. =>Without the traffic jam, we could have been in time for the game. =>But for the traffic jam, we could have been in time for game. 六. 代替if子句的用法

(除了if开始的副词子句外,不定词,副词片语,分词构句有时也有假设的功能) 1>不定词

If you heard him talk, you would think he knew all about the secret. =>To hear him talk, you would think he knew all about the secret.

2>副词片语/副词连接词

If I didn’t know he was innocent(无辜的), I wouldn’t try to save him. =>I know he is innocent, otherwise I wouldn’t try to save him. If we hadn’t hidden in the forest, they would have found us. =>We hid in the forest, otherwise they would have found us.

If you had a little patience ['pe?ns]耐心, you could get overyour difficulty. =>With a little patience, you could get over your difficulty.

If it had been ten years ago, I could have run around this lake within half an hour. =>Ten years ago, I could have run around lake within half an hour. 3>分词构句 Ving=主动 p.p.被动

The same men, if he were living in this century, would be a hero. =>The same men, living(主动) in this century, would b a hero. If you were seen from a distance, you might look handsome. =>Seen from a distance, you might look handsome. 4>作主词的名词

If he were a man of sense, he would not say such a thing. =>A man of sense wouldn’t say such a thing.

If he were a secret agent, he would never tell you his real name =>A secret agent would never tell you his real name.