成都考博辅导班

　　考博英语语法：虚拟语气归纳和练习
　　(5)as, 或者whether…or…谓语多用be的原形，引导让步虚拟从句，这种用法通常采用倒装结构：
　　Church as we use the word refers to all religious institutions, be they Christian, Islamivc, Buddhist, Jewish, and so on.
　　The business of each day, be it selling goods or shipping them, went quite smoothly.
　　(6)由连接词in case, so that ,unless, lest ,for fear that引起的状语从句中，谓语动词要用虚拟形式，即should(might, would) 动词原形，例如：
　　She put a blanket over the baby for fear that he should catch cold. 她在那个婴儿身上盖上了毯子以免他着凉。
　　The bad man was put in the soft-padded cell lest he injure himself.
　　(7) if it were not for…与现在事实相反， if it had not been for与过去事实相反，两个都相当于but for：
　　If it had not been for his help(=but for his help),we would not have succeeded.
　　(8) 虚拟语气用于as if(though)引起的方式状语从句和表语从句中，其动词形式与wish宾语从句的形式相同。