看连接词,就是that which who whom whose, where when why后面,如果后面缺主语或宾语就用逗号前的连接词,不缺酒用逗号后的连接词,如果缺主语用that which who,缺宾语用that which whom, 如果连接词前面的先行词(即被修饰的名词,一般都是连接词前的最后一个名词)是物,用that which,是人,用 who whom
在从句里看的,如 He is the person who is my teacher. (这里用who ,是因为后面出来的是动词,动词前事缺主语的,因此用主格的who) He is the person (whom) i usually turn to for help.(这里是缺定语从句的turn to 的宾语,因此用宾格)本回答被提问者和网友采纳