if 【2 】引诱的前提句中的虚拟语气虚拟语气表示一种不能实现的假设.该语法重要用于if前提状语从句.一.if引诱的前提状语从句的分类及虚拟前提句的断定1.可以把前提句分为两类：1).真实前提句（Sentences of Real Condition）：凡是假设的情形产素性可能很大,就是真实前提句.例如：⑴.If I have time , I will help you with thiswork.假如我有时光会关心你做此工作的.(2).If time permits, we'll go fishingtogether.(假若有时光的话,我们就一路去垂纶.）2).虚拟前提句（Sentences of UnrealCondition）：当假设是不大可能实现时,就是虚拟前提句.例如：⑴.If I were you , I would have attended the meeting.假如我是你的话,就去参加会议了.⑵.If he had come here yesterday, he would have seen his oldfriend.假如他昨天来这儿的话,就会看见他的老同伙.⑴.If it had rained yesterday, we would have stayed athome.（假如昨世界雨的话,我们就会留在家里.）2..if前提状语从句中虚拟语气的断定断定是真实前提句照样非真实前提句.只有在非真实前提句中才应用虚拟语气.经由过程句子意思,看假设的前提是否可以或许实现,可以或许实现是真实前提句,不能应用虚拟语气;假设的前提不能实现则长短真实前提句,要用虚拟语气.断定这个假设是与哪个事实相反.平日有三种情形：①与曩昔事实相反.②与如今事实相反.③与未来事实可能相反.3.“撤退退却一步法”撤退退却一步法是指在精确地断定了该句与哪一事实相反后,按虚拟语气的撤退退却一步法处理从句谓语动词的时态.即：在非真实前提状语从句中,谓语动词按正常情形“撤退退却一步”.也就是：①与曩昔事实相反,在从句顶用曩昔完成时情势表示.②与如今事实相反,在从句顶用曩昔一般时情势表示.③与未来事实可能相反,在从句顶用曩昔未来时情势表示.主句中则用情态动词would, should, could等加一个与从句一致的动词情势.例：⑴.If I had come her yesterday, I would have seen him.⑵.If I were a teacher, I would be strict with my students.⑶.If it should snow tomorrow, they couldn't go out.4.留意事项①if前提句中若有were, should,had,可以省去if,并应用倒装语序.②在现代英语中if前提状与从句中的谓语动词假如是be其曩昔情势一般用were.二.虚拟语气在if 引诱的前提句中的用法：（一）.表示与如今事实相反的情形.其句子构造为：从句：if + 主语+动词的曩昔式(be 用were) + ……主句：主语+ would (should, could , might) + 动词本相+ ……例：1.If I were you, I would go with him.2.If the weather were fine, I would gothere.假如气象好,我去那儿.（事实气象不好）3.If I were you, I would read itagain.假如我是你的话,我再读一遍.（事实上我不是你）4.If time permitted, I would write itagain.假如时光许可的话,我再写一遍.（事实上时光不许可）5.If it weren’t snowing, we wouldn’t stay in thehouse.如果如今不下雪的话,我们就不会待在屋里.（事实上如今下雪）6.What would I do if I were in yourplace?如果我处于你地位我会怎么办？（事实上我不在你的地位上）7.If he hurried, he could catch the firstbus.他如果快点可以或许赶上头班公共汽车.（可是他不焦急）8. If it weren’t for your help, we would get intotrouble.假如没有你们的关心,我们就会陷入困境.（而事实上得到了你们的关心）9.If we had the manpower, we could open up even more land.假若有人力,我们还能开更多的荒地.10. If I were you, I would go with him.(从句If I were you, 主句I would go with him.)11. If I were you, I should buyit.(从句用曩昔式动词were,主句用动词本相buy)12. If I had time, I would studyFrench.(假若有时光,我会进修法文.）（从句用曩昔式动词had,主句用动词本相study）13. If she knew English, she would not ask me forhelp.(假如她懂英文,她就不必要我帮了.)(从句用曩昔式动词knew, 主句用动词本相ask)留意：假如动作在进行中,主句要用："主语+ would be + 进行式动词+ ……"14. If they were here, he would be speaking to them now.(从句用曩昔式动词were, 主句用would be speaking)。
if引导虚拟语气的用法1、表示与现在事实相反的情况：从句：If主语+过去时(Be动词用were)主句：主语+XXXdoeg：1．If I were you,I would take an XXX.如果我是你，我会带把伞。
（事实：我不可能是你）2．If I knew his telephone number,I would tell you.如果我知道他的电话号码，我就会告诉你。
（事实：不知道）3．If there were no air or water,there would be no living things on the earth.如果没有水和空气，地球上就不会有生物。
(事实：地球上既有空气也有水)4．If I had any money with me,I could lend you some.假如我带钱了，我就会借给你些。
（事实：没有带钱）5．If he XXX,he might pass the exam.如果他再努力些，就能通过考试了。
（事实：没有努力）6．she looked at me as if I had been a stranger.她看我的样子好像我是一个陌生人。
（事实：我并非陌生人）2、表示与过去事实相反的情况从句：If主语+had+done主句：主语+should/would/could/might+have doneeg：1．If I had got there earlier,I should/could have met her.如果我早到那儿，我就会见到她。
事实：去晚了）2．If he had XXX my advice,he would not have made such a XXX.如果他听我的劝告的话，就不会犯这样的错误了。
事实：没有听我的话）3、透露表现对未来情形的客观推测主句：主语+should+do从句：①if+主语+were to do②if+主语+should/would/could/might+do③if+主语+did（动词过去式）/wereeg：1．If he should come here tomorrow,I would talk to him.如果他明天来这儿的话，我就跟他谈谈。
if 条件状语从句中的虚构语气一、 if 条件状从句中虚气的判断判断是真条件句是非真条件句。
只有在非真条件句中才使用虚气。
通句子意思，看假的条件能否能，能是真条件句，不可以使用虚气；假的条件不可以是非真条件句，要用虚气。
1. “退后一步法”退后一步法是指在正确地判断了句与哪一事相反后，按虚气的退后一步法理从句的。
即：在非真条件状从句中，按正常状况“退后一步”。
也就是：①与去事相反，在从句顶用去达成形式表示。
②与在事相反，在从句顶用去一般形式表示。
主句中用情would,③与未来事可能相反，在从句顶用去未来形式表示。
should, could等加一个与从句一致的形式。
例：⑴、 If I had come her yesterday, I would have seen him.⑵、 If I were a teacher, I would be strict with my students.⑶、 If it should snow tomorrow, they couldn't go out.2、注意事：① if 条件句中若有were, should, had，能够省去if ，并使用倒装序。
②在代英中if条件状与从句中的假如是be 其去形式一般用were 。
二、虚气在 if 引的条件句中的用法：（一）、表示与在事相反的状况。
其句子构：从句：if +主 + 的去式 (be用 were) + ⋯⋯，主句：主 + would (should, could , might) +原形 + ⋯⋯例：1. If it weren ’t for your help, we would get into trouble.假如没有你的帮助，我就会堕入窘境。
（而事上获得了你的帮助）the weather were fine, I would go there.假如天气好，我去那边。
（事天气不好）I were you, I would read it again. 假如我是你的，我再一遍。
1.if 条件状语从句中的虚拟语气一、if 条件状语从句中表示对将来、过去、现在的虚拟1. If she invites me tomorrow, I shall go to the party.（真实条件句）如果她明天邀请我参加聚会,我就去.If she invited me , I should go to the party.[虚拟条件句] (说话人认为邀请的可能性较小或不可能)She will probably not invite me, so I shall not go to the party.2. If she had invited me yesterday, I should have gone to the party.假如她昨天邀请我参加聚会,我就去了.She didn`t invite me yesterday, so I didn`t go to the party. 她昨天没有邀请我参加聚会,因此我没有去.3. If she should invite me tomorrow, I should go to the party.If she were to invite me tomorrow, I should go to the party.If she invited me tomorrow, I should go to the party.1.对现在的虚拟条件状语从句的动词形式主句的动词形式If+主语+动词过去式(be的过去式用were) I (we) should+动词原形主语+would(might, could)+动词原形If I were you, I should study English. (I am not you , so I shall not study English.)If I had time, I would attend the wedding. (I does not have time, so I will not attend the wedding.)If they didn`t take physical exercises every day, they wouldn`t be so healthy.(They take physical exercises every day, so they are very healthy.)2.对过去的虚拟条件状语从句的动词形式主句的动词形式If+主语+had+过去分词 I(we) should+ have+过去分词主语+would(might, could)+have+过去分词If you had taken my advice, you wouldn`t have failed in theexamination.(You did not take my advice, so you have failed in the examination.)3.对将来的虚拟条件状语从句的动词形式(三种) 主句的动词形式⑴If+主语+动词过去式(be的过去式用were),通常要与一个表示将来的时间状语连用(tomorrow)⑵If+主语(任何人称和数)+should+动词原形⑶If+主语(任何人称和数) +were +to动词原形I (we) should+动词原形或主语(任何人称)+would(might, could)+动词原形If it rained tomorrow, our picnic would be put off.If it should rain tomorrow, our picnic would be put off. If it were to rain tomorrow, our picnic would be put off.。
