定语从句中先行词为物时用that 或者which
先行词为人时用that或者who
This is the book which I bought yesterday.
I don;t like the man who I saw last night.
whom用于先行词在从句中作宾语时,一定要记住是在从句中作宾语!This is the man whom I talked with the other day.
上句who也可以用,但介词之后只能用whom
This is the man with whom I talked the other day.
此处只能填whom