高考英语二轮专题语法复习虚拟语气语法讲义15if的隐含和省略以及与butfor相关虚拟语气知识点总结.docx

高中英语语法学习/复习讲义虚拟语气语法知识点讲义15【精讲版·全国通用】if的隐含和省略以及与but for相关虚拟语气知识点总结虚拟条件句中if的隐含或省略 语言是灵活多变的，表达是丰富多彩的。有的时候虚拟语气的表现形式也显得非常灵活，比如就说其中的虚拟条件吧它有时会以if从句来表示，但有时会用某种短语来表示，比如不定式短语、分词短语、介词短语等等。1. if 的隐含I should be happy to go with you. 如果能与你一起去，我将很高兴。句中的不定式短语to go with you就是表示虚拟条件的，它相当于if I could go with you。这句话的言外之意是：可惜我不一定有机会同你一起去。To have studied harder, you would have passed the examination. 你学习更用功些，你早就考及格了。句中的不定式短语to have studied harder也是表示虚拟条件的，它相当于if you had studied harder。句子的言外之意是：可惜你当时没有更用功我，所以你就没有考及格。Failing this time, what would you do？假若这次失败，那你怎么办？句中的分词短语failing this time表示虚拟条件，相当于if you failed this time。其言外之意是：尽管失败的可能性很小，但还是有可能会失败，假若失败了，那怎么办？Without your help, we couldnt have succeeded. 如果没有你的帮助，我们就不会取得成功。句中的介词短语without your help表示虚拟条件，相当于if you hadnt given us help。其言外之意是：好在你帮助了我们，所以我们取得了成功。I didnt know that he was a cheat, or else I wouldnt have believed him. 我不知道他是个骗子，不然我也不会相信他了。句中的or else隐含着一个虚拟条件，它相当于if I had known he was a cheat。句子的言外之意是：当是我竟然相信了他。2. if 的省略在虚拟条件句中，有时可将引民虚拟条件句的连词if省略，但此时应用倒装句型，即将从句中的were, should, had 等提到句首。如：如果她在这里，她也同意的。If he were here, she would agree too.Were she here, she would agree too.假若明天下雨，我们只好推迟这场比赛。If it should rain tomorrow, we should have to put off the match.Should it rain tomorrow, we should have to put off the match.要是我们当时早点找到他的话，我们就可以救活他。If we had found him earlier we could have saved his life.Had we found him earlier we could have saved his life.注意，如果条件从句的谓语为否定式，其中的否定词not应置于主语之后，而不能与were, should, had 等缩略成Werent, Shouldnt, Hadnt而置于句首。我如不是警告了你，你就可能丧命了。正：If I hadnt warned you, you could have been killed.正：Had I not warned you, you could have been killed.误：Hadnt I warned you, you could have been killed.另外，有时省略if后提前到句首的had可能不是助动词，而是实义动词。如：Had I time, I would go with you. 假如我有时间，我就同你们一起去。句中的had不是构成过去完成时的助动词，而是表示“有”，如果不省略if，其完整形式为：If I had time, I would go with you. 表示“若不是”的虚拟语气句型 英语中有几个表示“若不是”“要不是”的固定表达，它们总是用于引出虚拟条件，句子谓语总是用虚拟语气。这几个句型是：1. but for它的意思是“要不是有”“若不是因为”，习惯上与虚拟语气连用。如：The car broke down. But for that we would have been in time. 汽车出毛病了。要不是那个我们会及时赶到的。But for the storm, I would have been home before eight. 要不是因为这场风暴，我早在8点钟以前就回到家里了。2. if it were not for主要用于谈论现在的情况，意思也是“要不是有”“若不是因为”，相应的主句总是用虚拟语气。如：If it werent for your help, I would still be homeless. 若非你的帮助，我仍会无家可归。If it were not for your quick play, our team would not win. 若没有你敏捷的技巧，我们球队是不会赢的。3. if it had not been for主要用于谈论过去的情况，意思也是“要不是有”“若不是因为”，相应的主句总是用虚拟语气。如：You wouldnt have seen her if it hadnt been for him. 如果不是因为他，你就不会见到她了。If it hadnt been for the doctors care, I wouldnt have recovered so soon. 要不是医生的照顾，我不会痊愈得这么快。说明：介词without有时也可表示虚拟条件，意为“若不是”“要不是”，与but for用法相同。如：Without =But for your help, I would have failed. 要不是有你的帮助，我就会失败了。但是，without也可以不表示条件，只表示“没有”的意思。如：Without a word he left the room. 没有说一句话他离开了房间。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 storm, we should have arrived earlier. 要不是碰到暴雨，我们还会早些到。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。如果but for不是表示if it were not for或if it had not been for这样的意思，而是构成not forbut for这样的搭配，或其中的but只是一个普通的转折连词，其后的for也只是一个普通的介词，此时显然不必与虚拟语气连用。如：Im not afraid for me, but for the baby. 我不是为我担心，而是为宝宝担心。We dont usually accept checks, but for you well make an exception. 我们通常接受支票，但对你我们可以破例。The sale was supposed to last for a week, but for all practical purposes its over. 减价销售原来预料要持续一周，然而实际上现在已经结束了。Youll have your own office soon but for the time being youll have to share one. 你很快就有自己的办公室了，不过暂时还得和别人合用一间。