If 条件句的用法1.ppt

虚拟（第三条件句·第四条件句） 这种是非真实条件句（unreal conditional) 的一种。所谓“非真实条件”，在语义上包含着不同程度的“非真实性”。这种类型的条件句也可分为基本形式和变体形式。 虚拟 基本类型 （if）simple past / were + (main) would (could ,might,etc) +inf 例如 If we caught the 10 oclock train, we would (could,might,ect)get there by lunch-time. 主句动词都用would could might ,etc 不定式。但可能性的程度不一样 If I knew how it worked, I could tell you what to do . (条件与现实相反，根本不可能告诉对方做什么） 虚拟 这种句型的动词形式还可根据语义意图采用进行体形式。 If we were on holiday now , we d be having a wonderful time 虚拟 变体形式 (If) were to +inf+(main)would,etc+inf 例： If our train were to arrive punctually, we should have time to visit your sister. 要注意表示非真实条件的were to 与表示“义务”（obligation） 的am / is / are to 和was/ were to 的区别 虚拟 If he were to get in touch with me , I could explain. = Supposing he got in touch with me...(非真实条件） If he was to get in touch with me , why hasnt he done so ? = If the arrangement was that he should get in touch with me , why...? (表示“义务”） 里一个变体是在if-分句中用would + 不定式 表示不大可能实现的意愿 If you d cook the dinner , id do the washingup afterwards.（省略 to) 虚拟 (If) had + -ed 分词 +Main would (could might,ect) have＋　-ed分词 例如 If we had caought the 10 oclock train ,we would have got there by lunch-time. We would /could /might have called you if we had known your telephone number　 虚拟 如果句子的前半段 （if -分句） 是表现现在不大可能实现的条件，而后半段（主句）却表示与过去事实相反的情况，前后在逻辑意义上不相协调。但在保证句子合乎逻辑的前提下，也可根据语义意图混合实用俩种句型的动词形式 If he had wanted to dance ,Id have taken him to discotheque(迪斯科舞厅） 虚拟 第四条件句的变体形式 （If）were to have + -ed 分词 +Main would (could, might, ect)have -ed 分词 例如 If you were to have asked me , I would have been only too willing to help. 虚拟 10分题 I used to walk to work.But if it ______(rain), I went by bus. rained 20分题 If you move to your left, you ____(be)able to see the church 30分题 He could repair the roof himself if he _____(have) a long ladder. had 40分题 If the story hadnt been ture, the newspaper _________(not print) it . wouldnt have printed if i w