Question

who和whom有什么区别，应该怎么用

Answer 1

Who (Subject)

1) When providing extra information about the subject in the sentence. 

2) When you are asking about the subject. 

例子：Ali is my friend who is a teach.

Who rang the doorbell?

Whom (Object) 

1) When providing extra information about the object in the sentence. 

2) When you are asking about the object.   

例子：Ali is the man whom I told you about. 

To whom did you give the notebook? 

Answer 2

who和whom都是代词（pronoun）。 但是，“who”用作一个句子或短语的“主语”（主语是谓语的陈述对象，如“我写字”中的“我”就是主语。），表示谁在做某件事（比如he或she）。 另一方面，“whom”充当一个动词或介词（preposition）的直接或间接“宾语”(object)。