1. 当关系代词用作主语时,多用主格who。例如:
He who loses hope loses all.
失去希望的人就失去一切。(先行词为代词he, they, any, all, one等时,多用who)
I met Alice, who told me that she was learning Chinese.
我遇见艾丽斯,她告诉我她在学汉语。(在非限制性定语从句中,用who)
2. 当关系代词用作介词后的宾语时,用宾格whom,不用that。例如:
The man to whom our headmaster talked just now is our English teacher.
我们校长刚才与他谈话的那个人是我们的英语老师。(介词与关系代词紧密相连时,只能用宾格whom,不可用主格who)