什么情况用虚拟语气 对过去现在将来分别怎样用虚拟

什么情况用虚拟语气 对过去现在将来分别怎样用虚拟

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虚拟语气
概述
英语的动词有三种语气形式,即陈述语气、祈使语气和虚拟语气.陈述语气用来说明事实或就事实提出询问,可用于陈述句、疑问句和某些感叹句中；祈使语气用于表示请求、命令、建议或警告等.
虚拟语气是谓语动词的一种特殊形式,用来表达假设、主观愿望、猜测、建议、可能或空想等非真实情况.如：
He is honest.他很诚实.（陈述语气）
Don‘t be late next time.下次别迟到.（祈使语气）
If I were you ,I would not go.我要是你,我就不会去.（虚拟语气）
I wish I had a lot of money.要是我有很多很多钱就好了.（虚拟语气）
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第一类
虚拟语气在条件句中的用法：
条件句有真实条件句和虚拟条件句两种.真实条件句所表示的假设是有可能发生的,此时主句不用虚拟语气；而虚拟条件句则表示一种假想,与事实相反或不大可能会发生,此时用虚拟语气.如：
If I have time,I will go.假若我有时间,我就去.（陈述语气） If I were you,I would go.假若我是你,我就去.（虚拟语气 ）
时态类型
主句谓语形式
条件句的谓语形式
例句
与现在事实相反
would/should/could/might+ V原形
动词过去式 did
*be 多用were
1.If I were you,I should study English.
2.I would certainly go if I had time.
与过去事实相反
would/should/could/might + have done
动词过去完成式
had done
1.If you had taken my advice,you would not have failed in the test.
2.If I had left a little earlier,I would have caught the train.
与将来事实相反
would/should/could/might + V原形
①动词过去式
②should +V原
③were + to do
1.If you came tomorrow,we would have the meeting.①
2.If it were to rain tomorrow,the meeting would be put off.③
*规律总结：从句都往过去推一个时态,如：与现在相反的if从句就用过去时；与过去相反用过去完成时（即过去的过去）
注：特别说明
1、l would/should/could/might主句谓语中的should主要用于第一人称后；would表示结果还表示过去经常常常做某事,might表示可能性,could表示能力、允许或可能性.比较：
If you tried again ,you would succeed.要是你再试一试,你就会成功的.(would表结果)
If you tried again,you might succeed.要是你再试一试,你可能会成功的.(might表可能)
If you tried again ,you could succeed.要是你再试一试,你就能成功了.(could表能力)
2、错综时间虚拟条件句 即条件从句与主句所指时间不一致,如从句指过去,而主句即指的是现在或将来,此时应根据具体的语境情况,结合上面提到的三种基本类型对时态作相应的调整：
If it had rained last night,the ground would be wet now.要是昨晚下过雨的话,现在地面就会是湿的.
You would be much better now if you had taken my advice.假若你当时听我的话,你现在就会好多了.
3、If虚拟条件句的否定（含蓄条件句） 常考两个句型：If it weren’t for…和If it hadn’t been for…,其意为“若不是(有)” “要不是”.如：
If it weren’t for water,no plant could grow.要是没有水植物就无法生长.
If it hadn’t been for your assistance ,we wouldn’t have succeeded.
=But for your assistance ,we wouldn’t have succeeded.
=Without your assistance ,we wouldn’t have succeeded.如果没有你的帮助,我们不会成功的.
4、If虚拟条件句的倒装形式,即把were,had,should置于句首.例：
Were I in school again (= If I were in school again),I would work harder.如果我能再上一次学,我会学习得更努力.
Had you asked me,I would have told you.(=If you had asked me,…)如果你问我,我会告诉你.