who whom whose在定语从句中怎样辨别?

问题描述:

who whom whose在定语从句中怎样辨别?
怎样运用这几个引导词

在从句中充当主语代人用who,I knew the man who beat him.
在从句中充当宾语代人用whom,I knew the man whom he beat.
在从句中充当物主代词用whose,I knew the man whose bike was stolen.
在口语中,whom 常被who代替.