3.第三章 假设语气(14-17).doc

3.第三章 假設語氣（14-17）直述句 If you are free, please help me with my homework.假设句 If I were free, I could help you with your homework. (委婉的拒绝)1） 与时态有关 （与动作有关）2） 事实与假设时态差一级（往前推）一假设法 现在式（表示现在或未来还不确定的假设）If +主词+现在式动词, 主词+(will/ shall) + VR If it rains tomorrow, we will cancel the picnic. (I think that it will rain tomorrow.)重点：下列两句型中，可用假设法现在式主词+动词(suggest, demand, insist, agree+ that+ 假设法现在式。1. I suggest that everyone (should) help in some way.2. I insist that she (should) consult the doctor.It is+形容词(necessary, important 等)+ that+ 假设法现在式It is important that she (should) be honest.假设句 与 Its important for her to be honest. 直述句二.假设法 过去式 (表示与现在事实相反的假设)If+主词+were (在假设句中的be 动词用were, 美语可能用was )S+ would, could, should, might+原形动词 过去式动词过去式助动词3. If I were young, I could enjoy this party. （事实）As I am not young, I cant enjoy this party.4. 如果我又很多钱， 我就买一艘游艇。If I were rich, I would buy a yacht, (假设)If I had a lot of money, I would buy a yacht. (假设) (事实) As I dont have a lot of money, I wont buy a yacht.三.假设法 过去完成式 （表示与过去事实相反的假设）If+主词+had+P.P. ,主词+ would/could/should/might+have+P.P. (助动词后面跟原型)1. If I had known the gossip then, I would have told (tell) you.(事实) As I didnt know the gossip then I wouldnt tell you.2. We would not have dozed off if our teacher had spoken louder.(事实) As our teacher didnt speak loud , we dozed off.注意：在条件句中，除了if 之外， 也可用 suppose (supposing), suppose that+S+V, providing (provided), as(=so) long as, in case; unless等。但是 unless通常不用于假设语气中的字句中。1. Suppose (= supposing) you had 10 million dollars, what would you like to do first?2. I will stay here provided (providing) that climate agrees with me tomorrow.重点： 假设法过去式及假设法过去完成时混合使用。 若两个字句的时间不同时，其时态 各自为准If I had done my homework yesterday, I would go on a date with her now.分析：If I had done my homework yesterday, 与过去事实相反用过去完成式。 I would go on a date with her now. 与现在事实相反用过去式。（事实）As I didnt do my homework yesterday, I dont go on a date with her now.四.假设法 未来式If+主词+ should/were to +V ,主词+will/would +V *should的出现在if子句当中，解释成万一* 万一/完全不会的万一明天下雨的话， 比赛将会延期。(下雨这件事，是有可能发生的，所以用should表示万一)If it should rain tomorrow, the game will/would be put off. (be put off被延期)如果太平洋干枯的话，我就会改变心意。（太平洋干枯这是不可能的事，所以用were 表示完全不会的可能）If the Pacific Ocean were to dry up, I would change my mind. （重点）假设句中， 也可将IF 省略，形成: were (had/ should) 等+主词的顺序。1. 如果我是一只鸟， 我就能够飞向你。If I were a bird, I could fly to you. = Were I a bird, I could fly to you.2. 如果他知道真相， 他会告诉你。If he had known the truth, he would have told you. = Had he known the truth, he would have told you.3. 万一下雨的话， 我就呆在家里。If it should rain, I would stay at home. = Should it rain, I would stay at home. (Should 放句首可以解释为万一)五： 假设法的其他表现 as if / as though + S + 好像/宛如假设法过去式假设法过去完成式1. He talks as if / as though he knew everything. 与现在事实相反用过去式, talks 现在式，knew 过去式2. She looks as if / as though she had seen a ghost. 与过去事实相反用过去完成式 （因为他过去没有看到鬼）3. He laughed as if / as though nothing had happened. 与过去事实相反用过去完成式 （其实是由事情发生的） wish + S +希望/但愿假设法过去式假设法过去完成式1. I wish I knew Annies cell phone number. 事实：Im sorry (that) I dont know Annies cell phone number.2. I wish I hadnt bought such an expensive dress then. 事实：Im sorry I bought such an expensive dress then.Itstime+ (that) + S + 假设法过去式 （一定用假设语气）about timealmost timehigh timeIts past midnight. Its time (that) the children went to be. = Its time for the children to go to bed.Its about time you apologized to her for what you did. = Its time for you to apologize to her for what you did. If only +主词+假设法过去式假设法过去完成式注意：If only 和I wish 在表现上意思差不多If only my teeth would stop hurting. 但愿我的牙齿不疼了。If only I had taken her advice.但愿那时我有接受她的忠告。（事实他没接受她的忠告（过去的事情与过去的事实相反If it were not for 假设法过去式If it had not been for 假设法过去完成式If it were not for music, he couldnt live a moment,Were it not for music, he couldnt live a moment.Without music, he couldnt live a moment.But for music, he couldnt live a moment. *but for 要不是假若but for表示if it were not for或if it had not been for这样的意思（即表示“若不是”“要不是”），它一定要与虚拟语气连用。如But for your help we couldnthave succeeded in the experiment. 如果没有你的帮助，我们的实验是不会成功的要是那时没有赛车，我们就能及时赶上比赛。If it had not been for traffic jam, we could 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 the game.六 代替 if 字句的用法A. 不定词 (TO + V)1. 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.B. 副词连接词 /副词片语 1. If I didnt know he was innocent, I wouldnt try to save him.= I know he is innocent; otherwise I wont try to save him.2. If we hadnt hidden in the forest, they would have found us.= We hid in the forest; otherwise they would have found us.3. If you had a little patience, you could get over your difficulty. (表示事实上没有耐心)= With a little patience, you could get over your difficulty. (with也是有的意思)4. If it had been ten years ago, I could have run around this lake within half an hours.= Ten years ago, I could have run around this lake within half an hour.C. 分词构句1. The same man, if he were living in this century, would be a hero.= The same man, living in this century, would be a hero. Living 主动2. If you were seen from a distance, you might look handsome.= Seen from a distance, you might look handsome. Seen 被动D作主词的名词1. If he were a man of sense, he would not say such a thing.= A man of sense, he would not say such a thing.2. If he were a secret agent, he would never tell you his real name.= A secret agent would never tell you his real name.but for一定要与虚拟语气连用吗假若but for表示if it were not for或if it had not been for这样的意思（即表示“若不是”“要不是”），它一定要与虚拟语气连用。如：But for his pension, he would starve. 要不是他有养老金，他就挨饿了。But for the