1、虚拟语气大概况一，假设句 if表示的是与： “事实相反的事”为条件，提出：“与事实相反的结论”1， 与现在事实相反条件句 主句If+s+过去式分词 (done) s+should/could/would/might+do(动词的原形)Be 动词（were）没有人称限制 例句A. If I knew his address, I would write to him.B. If I were a boy, I might get married with her.C. If I could fly, I would fly to you.D. If I had enough money ,I c
2、ould buy that car.2,与过去事实相反条件句 主句If + s+ had+过去分词（done ） s+would/could/should/might+have+ 过去分词（done ）例句Aif I had known your address, I would have written to you.B If it had not rained yesterday, I would have gone fishing.C If she had been there that night, she might had been hurt.3,与将来事实相反，分为两类，主观上，
3、和客观上A 主观上，“万一” 发生的可能性很小，但是有可能发生条件句 主句If +s+shoud+动词原形（ do）。 s+would/could/should/might+ 动词原形（do）例句A. if it should rain tomorrow, I would go.B. If she should come tomorrow, we would marry.C. What should I do if I should fail ?B 客观上，完全不可能发生的事情条件句 主句If +s+were+ to+动词原形（ do） s+would/should/could/might+动
4、词原形（do）Were 不受人称的限制例句Aif the sun were to rise in the west, I would follow you.B If you were to give me ten million dollars, I would marry you.上面介绍了 if 的最基本集中虚拟从句，主句和从句，注意前后对照，如，主句是过去时，从句相应的搭配，必须牢牢记住基本结构，下面是两个特殊的例子，一般不用，只在一些阅读中出现，看到了也不要觉得错特殊例子：如果过去。，你现在就不会。表示这个意思A. 如果你昨晚念书的话，现在就能回答这个问题了 if you had st
5、udied last night ,you could answer this question.切忌这个我们一般不用，千万别和以上讲的那些混了。二，省略 if条件句里的谓语动词如果是 were, should,could,had,此时引导条件句的 if 就可以省略掉，但是，词序得变动，谓语动词 were, should,could,had 得放在主语的前面。条件句 主句If+s+were s+should/could/would/might+do(动词原形)Should Could +do(动词原形)Had have done这个句型就可以省略 if,变成条件句 主句WereHad +s s
6、+ should/could/would/might+do(动词原形)ShouldCould例句Aif I had known you had company, I would not have dropped in.had I kown you had company, I would not have dropped inB. if the sun were to rise in the west, I would follow you.Were the sun to rise in the west, I would follow you.C if anyone should come
7、in my absence, he should wait for me.Should anyone come in my absence, he should wait for me.三，含有假设意义的词，通常表示“与事实相反”“难于实现”1，作为方式状语： as if as though(好像是，其实不是)He lives as if he were a millionaire.(表现在时态, as if 后面的从句就用一般过去时)He turned pale as if he had seen a ghost. (表示过去的时态，as if 后面的从句就用 had +done)2，让步状
8、语 ：even if even thoughEven if I were there, I would say something.（时态的用法，主句从句前后一致，和我们前面提到的 if 引导的条件从句是一样的使用方法，我就不解释了，如果有问题，可以提问）3,wish , if only, oh that , would that, would rather, would soon, had just as soon 都表示与事实不符的愿望例句A. 表示与现在的不符合，所以用一般过去式 were,did)I wish I were a bird .(I wish I had bought th
9、e house last year.(表示过去，所以用过去完成时 had done)B. if only I knew the answer .要是我知道答案该多好啊。COh that money grew the trees.钱要是长在树上该多好啊。D Would that I were young again.我要是能再年轻就好了。Ei would rather/soon/had just as soon he did not go.他要是没走。以上这几个例句就是这些词的用法，我们会发现一个共同的特点，它们其实在时态上面很简单：如果是表示现在的话，就用一般过去时 did(动词的过去式)/w
10、ere过去的事，就用过去完成时 had done.4,but for (假定没有)=withoutA. But for your help, I would fail.表示现在的话，就是s+should/could/would/might+do(动词原形)B. but for your help yesterday , I would have lost my way.表示过去的话，就是 s+would/could/should/might+have+过去分词（done ）Cwithout=if it were not for.对于现在If it had not been for.对于过去Wi
11、thout (if it were not for )money ,I would not be alive.（表示现在）Without(If it had not been for)your help, I would/could should/might have failed.(表示过去)5，otherwise( 不然的话)A. I am busy, otherwise I would go.句子中的 otherwise 可以用 if I were not busy，理解起来就是这个意思。它表示的现在的时态，所以后面就是 s+should/could/would/might+do(动词原
12、形)B he worked hard , otherwise he would have failed句子中的 otherwise 可以用 if he had not work hard 来代替的, 它表示的过去的时态，所以后面的就是 s+would/could/should/might+have+过去分词（done ）注意，在学习这些词的用法的时候，其实我们刚才第一个学的 if 是最基本的，这些都是它的用法很接近的。学习时注意联系。四，省略 should 的用法有些词表示“提议”“建议“”“主张”“要求”“ 命令”“策略” 的动词，名词，形容词，它们后面跟的从句都表示该做或者不该做什么，th
13、at(should)do,此时 should可以省略的。1， 提议：suggest propose recommend move2， 主张：insist maintain hold urge3， 要求：ask require request demand desire stipulate4， 命令：order command统一的句型：s+ v(do)+that+s+dos+v(did 过去式)+that +s+do,这个句子之所以还是动词原形，是因为省略了 should.这些词的一部分有它的名词和形容词，遇到这种情况，还是利用上面的统一句型。Athe king gave the order
14、that these slaves be set free.这个句子就是 order 名词形式B 这个是动词 I suggested that we adopt a different policy.C 记得如果有这些意义的词，都是省略 should 的用法，得掌握最基本的。多见就熟悉了。It is necessary/enssential/vital/important/imperative/urgent/advisable/proper/mandatory/obligatory +that+s+(should)+do,DIt is urgent that a new law be cant
15、ed to protect children.五，目的状语In order that , so that +(should)do ,同样省略 should.例句 they climbed to the top of the building so that they get a birds eye view of the city.六，从句以 In case, for fear, lest 引导, 表示否定目的，动词用（should） do .同样省略 should.He ran away for fear that he be caught by the enemy.为了不让敌人抓住。He
16、took his umbrella in case it rain.七，定语从句It is (high) time that +s+did(过去分词) 表示该做什么了It is time we were off我们该离开了。八。简单句1，表示祝愿，诅咒的，用动词原形Long life our mother land.God bless you.2,表示“要是。该多好” 如 but for ,without,under 引导的状语。Under more favourable conditions ,we could have got a still life.3,分词短语Given more t
17、ime ,I would have done it better.4,不定式It would be a mistake not to help him.以上介绍虚拟语气大概况一，假设句 if表示的是与： “事实相反的事”为条件，提出：“与事实相反的结论”1， 与现在事实相反条件句 主句If+s+过去式分词 (done) s+should/could/would/might+do(动词的原形)Be 动词（were）没有人称限制 例句A. If I knew his address, I would write to him.B. If I were a boy, I might get marr
18、ied with her.C. If I could fly, I would fly to you.D. If I had enough money ,I could buy that car.2,与过去事实相反条件句 主句If + s+ had+过去分词（done ） s+would/could/should/might+have+ 过去分词（done ）例句Aif I had known your address, I would have written to you.B If it had not rained yesterday, I would have gone fishing
19、.C If she had been there that night, she might had been hurt.3,与将来事实相反，分为两类，主观上，和客观上A 主观上，“万一” 发生的可能性很小，但是有可能发生条件句 主句If +s+shoud+动词原形（ do）。 s+would/could/should/might+ 动词原形（do）例句A. if it should rain tomorrow, I would go.B. If she should come tomorrow, we would marry.C. What should I do if I should f
20、ail ?B 客观上，完全不可能发生的事情条件句 主句If +s+were+ to+动词原形（ do） s+would/should/could/might+动词原形（do）Were 不受人称的限制例句Aif the sun were to rise in the west, I would follow you.B If you were to give me ten million dollars, I would marry you.上面介绍了 if 的最基本集中虚拟从句，主句和从句，注意前后对照，如，主句是过去时，从句相应的搭配，必须牢牢记住基本结构，下面是两个特殊的例子，一般不用，只
21、在一些阅读中出现，看到了也不要觉得错特殊例子：如果过去。，你现在就不会。表示这个意思A. 如果你昨晚念书的话，现在就能回答这个问题了 if you had studied last night ,you could answer this question.切忌这个我们一般不用，千万别和以上讲的那些混了。二，省略 if条件句里的谓语动词如果是 were, should,could,had,此时引导条件句的 if 就可以省略掉，但是，词序得变动，谓语动词 were, should,could,had 得放在主语的前面。条件句 主句If+s+were s+should/could/would/mi
22、ght+do(动词原形)Should Could +do(动词原形)Had have done这个句型就可以省略 if,变成条件句 主句WereHad +s s+ should/could/would/might+do(动词原形)ShouldCould例句Aif I had known you had company, I would not have dropped in.had I kown you had company, I would not have dropped inB. if the sun were to rise in the west, I would follow y
23、ou.Were the sun to rise in the west, I would follow you.C if anyone should come in my absence, he should wait for me.Should anyone come in my absence, he should wait for me.三，含有假设意义的词，通常表示“与事实相反”“难于实现”1，作为方式状语： as if as though(好像是，其实不是)He lives as if he were a millionaire.(表现在时态, as if 后面的从句就用一般过去时)
24、He turned pale as if he had seen a ghost. (表示过去的时态，as if 后面的从句就用 had +done)2，让步状语 ：even if even thoughEven if I were there, I would say something.（时态的用法，主句从句前后一致，和我们前面提到的 if 引导的条件从句是一样的使用方法，我就不解释了，如果有问题，可以提问）3,wish , if only, oh that , would that, would rather, would soon, had just as soon 都表示与事实不符的
25、愿望例句A. 表示与现在的不符合，所以用一般过去式 were,did)I wish I were a bird .(I wish I had bought the house last year.(表示过去，所以用过去完成时 had done)B. if only I knew the answer .要是我知道答案该多好啊。COh that money grew the trees.钱要是长在树上该多好啊。D Would that I were young again.我要是能再年轻就好了。Ei would rather/soon/had just as soon he did not go
26、.他要是没走。以上这几个例句就是这些词的用法，我们会发现一个共同的特点，它们其实在时态上面很简单：如果是表示现在的话，就用一般过去时 did(动词的过去式)/were过去的事，就用过去完成时 had done.4,but for (假定没有)=withoutA. But for your help, I would fail.表示现在的话，就是s+should/could/would/might+do(动词原形)B. but for your help yesterday , I would have lost my way.表示过去的话，就是 s+would/could/should/mig
27、ht+have+过去分词（done ）Cwithout=if it were not for.对于现在If it had not been for.对于过去Without (if it were not for )money ,I would not be alive.（表示现在）Without(If it had not been for)your help, I would/could should/might have failed.(表示过去)5，otherwise( 不然的话)A. I am busy, otherwise I would go.句子中的 otherwise 可以用
28、if I were not busy，理解起来就是这个意思。它表示的现在的时态，所以后面就是 s+should/could/would/might+do(动词原形)B he worked hard , otherwise he would have failed句子中的 otherwise 可以用 if he had not work hard 来代替的, 它表示的过去的时态，所以后面的就是 s+would/could/should/might+have+过去分词（done ）注意，在学习这些词的用法的时候，其实我们刚才第一个学的 if 是最基本的，这些都是它的用法很接近的。学习时注意联系。四
29、，省略 should 的用法有些词表示“提议”“建议“”“主张”“要求”“ 命令”“策略” 的动词，名词，形容词，它们后面跟的从句都表示该做或者不该做什么，that(should)do,此时 should可以省略的。1， 提议：suggest propose recommend move2， 主张：insist maintain hold urge3， 要求：ask require request demand desire stipulate4， 命令：order command统一的句型：s+ v(do)+that+s+dos+v(did 过去式)+that +s+do,这个句子之所以还是
30、动词原形，是因为省略了 should.这些词的一部分有它的名词和形容词，遇到这种情况，还是利用上面的统一句型。Athe king gave the order that these slaves be set free.这个句子就是 order 名词形式B 这个是动词 I suggested that we adopt a different policy.C 记得如果有这些意义的词，都是省略 should 的用法，得掌握最基本的。多见就熟悉了。It is necessary/enssential/vital/important/imperative/urgent/advisable/prop
31、er/mandatory/obligatory +that+s+(should)+do,DIt is urgent that a new law be canted to protect children.五，目的状语In order that , so that +(should)do ,同样省略 should.例句 they climbed to the top of the building so that they get a birds eye view of the city.六，从句以 In case, for fear, lest 引导, 表示否定目的，动词用（should）
32、do .同样省略 should.He ran away for fear that he be caught by the enemy.为了不让敌人抓住。He took his umbrella in case it rain.七，定语从句It is (high) time that +s+did(过去分词) 表示该做什么了It is time we were off我们该离开了。八。简单句1，表示祝愿，诅咒的，用动词原形Long life our mother land.God bless you.2,表示“要是。该多好” 如 but for ,without,under 引导的状语。Under more favourable conditions ,we could have got a still life.3,分词短语Given more time ,I would have done it better.4,不定式It would be a mistake not to help him.以上介绍的这几种多在口语中出现，不做掌握，知道就好。
