lf从句谓语动词和主句谓语的动词lf从句谓语动词 主句谓语的动词pastpresentfuture

问题描述:

lf从句谓语动词和主句谓语的动词
lf从句谓语动词 主句谓语的动词
past
present
future

是虚拟语气吗?
If i had been there,i woule have helped you .
If i were you,i would go shopping now.
If it should be done by tomorrow,i would do it from now on.

if 引导条件状语从句 “主将出现”——主句将来时从句一般现在时