语法专题复习语法专题复习If 从句的谓语形式从句的谓语形式主句的谓语形式主句的谓语形式现在现在 did / werewould/could/should/might + do过去过去 had donewould/could/should/might+have done将来将来did / wereshould do were to dowould/could/should/ might + doIf If 条件状语从句用于虚拟语气条件状语从句用于虚拟语气*wishwish+ did(与事实相反的情况与事实相反的情况, )+ had done(与过去事实相反与过去事实相反)+would /could/ might +do(将来不大可能实现的愿望将来不大可能实现的愿望 )虚拟语气虚拟语气几个特例几个特例1. if only 意为：若是意为：若是.那该多好啊那该多好啊; 真希望真希望.; 只要只要, 只要只要.就好就好 表示现在的情况表示现在的情况,应用过去式应用过去式; 如果是过去的情如果是过去的情况况,应用过去完成时态应用过去完成时态 If only I had arrived in time !If only she didnt drive so fast.2as if / as thoughas if / as thoughdid 与现在事实相反的与现在事实相反的had done 与过去事实相反或想与过去事实相反或想象的事物象的事物4.would rather 后面的从句用虚拟语气：后面的从句用虚拟语气：I would rather you didnt come today.I would rather you didnt come tomorrow.I would rather you hadnt come yesterday.虚拟语气虚拟语气几个特例几个特例虚拟语气虚拟语气几个特例几个特例2. Its (high/right) time that that 从句要用虚拟语气：从句要用虚拟语气：过去时过去时或或should + do Its time that you left/should leave here.DemandSuggestOrderProposeRequestCommandInsistetc+(should ) do表示愿望、建议、命令、请求等表示愿望、建议、命令、请求等主语从句主语从句主语从句主语从句中的虚拟语气中的虚拟语气中的虚拟语气中的虚拟语气例句例句1.Its necessary that we should have a walk now. 2.Its important that we should take good care of the patient. 3在句型在句型 “It is important (necessary, strange, natural) that . ” 中，中，that 后面的从句中的谓语动后面的从句中的谓语动词用：词用： should + 动词原形动词原形 Without/But for your help, we would not have made such rapid progress.=If it hadnt been for your help.I have to leave right away , otherwise I would be late for the train. I would/could have helped you , but I was busy at that time. 虚拟语气虚拟语气几个特例几个特例3. 一些介词短语一些介词短语, 如如:but for(要不是要不是), without, otherwise(否则否则), 等等表示含蓄表示含蓄的条件的条件,这时主句要用虚拟语气这时主句要用虚拟语气5.情态动词用于虚拟语气：情态动词用于虚拟语气： could /might /have done should(not) have done ought(not) to have done neednt have done 虚拟语气虚拟语气几个特例几个特例5.情态动词用于对过去情况的推测：情态动词用于对过去情况的推测： must have done（肯定句）（肯定句） may/might /could have done （肯定句）（肯定句） cant/ couldnt have done （否定句）（否定句） can /could have done (疑问句）疑问句） 1 1、句句句句子子子子谓谓谓谓语语语语是是是是gogo，comecome，run run 等等等等表表表表示示示示位位位位置置置置的的的的动动动动词词词词和和和和bebe动动动动 词词词词，句句句句中中中中又又又又有有有有表表表表示示示示方方方方位位位位的的的的副副副副词词词词( (如如如如therethere，herehere，upup， downdown，outout，inin，awayaway等等等等) )，为为为为了了了了强强强强调调调调该该该该副副副副词词词词，可可可可将将将将其其其其放放放放于句首，而将谓语动词全部置于主语之前。如于句首，而将谓语动词全部置于主语之前。如于句首，而将谓语动词全部置于主语之前。如于句首，而将谓语动词全部置于主语之前。如: : Here comes the train to Beijing. 去北京的火车来了。去北京的火车来了。 There goes the bell. 铃响了。铃响了。 Down came the rain. 下雨了。下雨了。但主语是人称代词时，主语仍置于动词之前。如但主语是人称代词时，主语仍置于动词之前。如: Away he comes. 他来了。他来了。 Here it comes. 它来了。它来了。2 2、为为了了强强调调句句中中的的状状语语或或表表语语，为为了了保保持持句句子子平平衡衡或或上上下下文文衔衔接接紧紧密密，可可将将状状语语或或表表语语置置于于句句首首，句句中中主主语语和和谓谓语语完完全全倒倒装。如装。如: : At the front of the hall sat the headmaster. Hanging on the wall are two maps of China Present at the meeting were 200 teachers and 500 students. 3 3、为为了了强强调调onlyonly及及其其所所修修饰饰的的状状语语( (通通常常是是副副词词、介介词词短短语语或或从句从句) )，则将它们移到句首，句中的主谓作部分倒装。如，则将它们移到句首，句中的主谓作部分倒装。如: : Only then did we realize that the man was blind. Only when the war was over in 1918 was he able to get happily back to work.4、将将含含有有否否定定意意义义的的副副词词(never，seldom，not，little，hardly等等)置置于于句句首首以以示示强强调调时时，句句中中的的主主谓谓作作部部分分倒倒装装。如如:Seldom in my life have I met so determined a person.一生中我很少见到如此果断的人。一生中我很少见到如此果断的人。In no other places can you see such a sight. Not a single word did he say at the last meeting.在上次会议上他一句话都没说。在上次会议上他一句话都没说。 Hardlywhen，No soonerthan，Scarcelywhen, not onlybut also引引导导两两个个分分句句时时，将将前前一一个个分分句句中中的的主主谓谓作作部分倒装，后一个分句中的主谓语序不变。如部分倒装，后一个分句中的主谓语序不变。如: Hardly had he begun to speak when his father stopped him. No sooner had I left my house than it began to rain. 但但 neither / notnor 引导两个分句时，这两个分句中引导两个分句时，这两个分句中的主谓均要倒装。如的主谓均要倒装。如:Neither do I know her address，nor does he.我不知道她的地址，他也不知道我不知道她的地址，他也不知道.The patient could not eat, nor could he drink.那个病人既不能吃，也不能喝。那个病人既不能吃，也不能喝。7、在、在“so+形容词或副词形容词或副词/such+名词名词that分句分句” 结构中，结构中， so ,such 位于句首时，句子部分倒装。位于句首时，句子部分倒装。 So moved was she that she could not say a word. Such rapid progress has he made that all the teachers feel proud of him. 8. as 用于让步状语时的特殊结构用于让步状语时的特殊结构Young as he is , he knows a lot about the current Young as he is , he knows a lot about the current situationsituation. . 由于语法结构的需要，还有下列句型用于倒装句由于语法结构的需要，还有下列句型用于倒装句:1、“So + 助助动动词词 + 主主语语” 是是一一种种常常用用于于对对前前面面所所说说的的情情况作简短回答的句型。如况作简短回答的句型。如: I was late and so was she. 我迟到了，她也迟到了。我迟到了，她也迟到了。 They love making lots of friends, so do those with disabilities. 他们喜欢广交朋友，残疾人也一样。他们喜欢广交朋友，残疾人也一样。 2、“Neither / Nor + 助助动动词词 + 主主语语” 是是用用于于对对前前面面所所说说的否定内容表示同样看法的句型。如：的否定内容表示同样看法的句型。如： She wont go. Neither / Nor will I.她不走，我也不。她不走，我也不。 I cannot swim. Neither can he (swim).我我不不会会游游泳泳，他他也不会。也不会。3、当当if引引导导的的虚虚拟拟条条件件从从句句中中含含有有had，were或或should等等时时，如如将将if省省略略，则则要要将将had，were或或should等等移移到到主主语语前前，作部分或完全倒装。作部分或完全倒装。 Had you come yesterday，you would have seen him. (If you had come yesterday, you would have seen him.)