Who vs Whom ~ for beginners

 Who vs Whom ~ for beginners

WHO is used as the subject of a question. It refers to people.

Example:
Q: Who is 'she'?
A: She's our new English teacher.

WHO is usually followed by a singular verb even if the speaker is asking about more than one person.

Example:
Q: Who 'is' coming to dinner tonight?
A: Barry, Michelle, and Graham.

WHOM is used as the object of a verb or preposition. In spoken English, whom is rarely used; WHO is used instead. Whom is used only in formal question.

Example:
Q: Who(m) did you see?
A: I saw Mike.

»Note: WHOM, not WHO, is used if preceded by a preposition.

Example:
Q: To whom should I talk?
A: The secretary.