1、who指人在从句中做主语　　。(1) The boys who are playing football are from Class One.在踢足球的男孩们是一班的.　　。(2) Yesterday I helped an old man who lost his way.昨天，我帮助了一个迷路的老人.　　。2、whom指人，在定语从句中充当宾语，常可省略。（注：who和whom已无太大区别，可以通用。）　　。(1) Mr.Liu is the person (whom) you talked with on the bus.刘先生就是在公交车上和你聊天的那个人.　　。(2) Mr.Ling is just the boy whom I want to see.凌先生恰巧就是我想见的那个男孩.　　。