if的条件状语从句的三种用法
方法/步骤
1
if 的条件从句分为真实条件从句和虚拟条件从句.而真实条件从句适用于主将从现,是假设有可能发生的.而虚拟条件从句是假设不太可能发生的. IF的虚拟语气有三种：
2
与现在事实相反 动词过去式（be用were） would/could/should/might+动原例句：If i were you ,I would/could/should/might do that.
3
与过去事实相反 had+动词过去分词 would/could/should/might+have+动分例句：If i had know that yesterday,I would/could/should/might have told you .
4
与将来事实相反 should/were to+动原 would/could/should/might+动原例句：If it should rain ,the crops would/could/might be saved.