if引导的条件状语从句可不可以省略，if在虚拟语气中的用法

if引导的条件状语从句可以省略。

1）.在口语中，时常省略主语和谓语动词的一些。比如：(1).If(it is )necessary,I will come to help you.

(2).If(its )possible,I plan to see my parents every week.

2).在虚拟条件句中，从句中有should,were,had等，可以省略if,把should,were和had前提到句首，形成倒装句。

比如（1）If Chenglong should come to our little village tomorrow,I could see him with my own eyes.可以转换成Should Chenglongcome to our little village,I could see him with my own eyes.

(2)If he had finished his homework yesterday,he would have called me up.可以转换成Had he finished his homework yesterday,he would have called me up.

(3)If I were to fly to Hainan tomorrow,I would have a chance to have a dive.可以转换成Were I to fly to Hainan tomorrow,I would have a chance to have a chance to dive.

可以的，从句为主语（与主句完全一样）加be动词（have been也算）时省略，if necessary/possible等当成省略了it is

if的虚拟语气用法：

1、目前时:当if引导的虚拟语气表示与目前事实相反时，主句谓语用could、would、shoul d或mi ght加动词原形，条件从句中的谓语用过去式。

2、过去时:当if引导的虚拟语气表示与过去事实相反时，主句谓语用could、would、shoul d或mi ght加have再加动词原形，

3、以后时:当if引导的虚拟语气表示与以后事实相反时，主句谓语用could、would、shoul d或mi ght加动词原形，条件从句中的谓语用过去式。



虚拟语气中，表条件的状语从句的if可以省略，但主语一定要与动词易位（其实就是常说的倒装）：

If it were not for his illness, he could do better.

=Were it not for his illness, he could do better.

假设不是因为他生病，他可以做得更好。

If he had money, he would buy that villa.

= Had he money, he would buy that villa.



对以后情况的虚拟：

主句：主语＋would/should/might/could＋动词原形

从句：should＋动词原形/were to＋动词原形。

对目前情况的虚拟：

主句：主语＋would/should/might/could＋动词原形

从句：动词过去式



对过去情况的虚拟：

主句：主语＋would/should/might/could have＋动词过去分词

从句：had＋动词过去分词

指的是与过去情况相反的虚拟条件句。

虚拟条件句中假设谓语动词含有were, should, had这哪些词，可以把were, should, had放在if的位置，并去除if：那就是虚拟条件句的倒装。但已经没有if了。 如：