四六级常考语法点预览：

一、虚拟语气

基本规则：

条件从句

主句

与现在事实相反

动词过去式

should/would+动词原形

与过去事实相反

had+过去分词

should/ would +have+过去分词

与将来事实可能相反

动词过去式/were to/should

should/ would +动词原形

与现在事实相反：

If I wereyou , I would apply forthe job.

与过去事实相反：

If I had taken your advice, I wouldn’t have made such mistake.

与将来事实相反：

If itrained tomorrow, I wouldstay at home.