1、If条件状语从句,真实条件句： 、If I have time , I will help you with this work. 、If you have finished the homework, you can go home 、If time permits, well go fishing together. （4）If you heat ice，it turns to water. 表示在某条件下，某事很可能发生，条件是可能存在的，主句中某种情况发生的概率也是很高的。 ）,虚拟条件句： 、If I were you , I would have attended the meet
2、ing. 、If he had come here yesterday, he would have seen his old friend. 、If it had rained yesterday, we would have stayed at home.表示不可实现的条件或根本不可能存在的条件，也就是一种虚拟的条件或假设。,“后退一步法”,后退一步法是指在准确地判断了该句与哪一事实相反后，按虚拟语气的后退一步法处理从句谓语动词的时态。即：在非真实条件状语从句中，谓语动词按正常情况“后退一步”。也就是： - 与过去事实相反，在从句中用过去完成时形式表示。 与现在事实相反，在从句中用过去一般
3、时形式表示。 与将来事实可能相反，在从句中用过去将来时形式表示。 - 主句中则用情态动词would, should, could 等加一个与从句一致的动词形式。,If I were you, I would invite him to the partyIf I knew his new address, I would tell you. I would have arrived much earlier if I had not been caught in the trafficIf she were to/should come, I would tell her the secret
4、.,虚拟条件句的倒装,虚拟条件句的从句部分含有 were, should, 或 had 时, 可省略if，再把 were, should或had 移到从句的句首，实行倒装 .,1.Were they here now, they could help us,=If they were here now,2. Had you come earlier, you would have met him,=If you had come earlier,3. Should it rain, the crops would be saved,=Were it to rain,NOTE!,If I wer
5、ent here, he might not feel so nervous. A. Werent I here B. Were not I here C. Were I not here正确答案：C,If it _ last night，It would be very cold today.A. rained B. rains C. had rained D. would rain,错综时间虚拟条件句,有时条件从句和主句所表示的动作在时间上可以不一致（例如一个与过去事实相反，另一个与现在事实相反），这种虚拟条件句就称为错综时间虚拟条件句。,1. If I _ where he lived,
6、 I _ a note to him. A. know, would have sent B. had known, would have sent C. know, would send D. knew, would have sent2. If you had enough money, what _? A. will you buy B. would you buy C. would you have bought D. will you have bought,3. What _ if there _ no light during the day? A. will happen; w
7、as B. would happen; is C. happens; were D. would happen; were 4. If it _ not for the fact that you _ ill now, I would surely punish you. A. is; are B. were; were C. were; are D. was; were,5. If Henry had not pulled his cap low over his brow, he _ by the police. A. might be recognized B. might have b
8、een recognized C. would have recognized D. was to have been recognized,If the factory _ (belong) to me, I _ (not sell) it. But it isnt yours. 2. If you _ (keep) the secret, nobody _ (know) it. Im sorry for making such a mistake. 3. If the weather were to be (be) fine tomorrow, I _ (go) for an outing with my parents.,4. _ (be) I you, I would think about this problem once again. 5. _ (have) I had time last night, I _ (go) to see this wonderful film.6. If he _(receive) six more votes， he _ (be) our chairman now.,
