who whom whose在定语从句中怎样辨别?怎样运用这几个引导词

1.在从句中做主语代人用who, I knew the man who was singing then.
2.在从句中做宾语代人用whom, I knew the man whom you shook hands with.
3.在从句中作定语用whose, I knew the man whose father was dead.

whom 前面应该都有介词
whose应该是'谁的'意思
其他通常都是who

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.