whose在从句中作定语,后面必须有名词；who作主语或宾语.
The book （whose cover is blue） is mine.封皮是蓝色的那本书是我的.
The man who is in white is my father.穿白色衣服的那个人是我爸爸.（主语）
The man who/whom you talked to just now is my father.刚才跟你说话的那个人时我爸爸.（宾语）
The man to whom you talked just now is my father.(句中whom不可用who,两个都可做宾语,但前面有介词时不能用who,只能用whom.）致学