Mistake: Who vs Whom
who = subject; whom = object.
Examples
- Who called? To whom?
Key rules
- Who is the subject of a verb: Who called?
- Whom is the object of a verb or preposition: To whom did you write?
- In everyday speech, who is more common in both positions
Common mistakes
- To who did you write? → To whom did you write?
- Who did you invite? (object) → Whom did you invite? in formal writing
Use cases
- Formal letters
- Academic writing
- Grammar exams
💡 Tip: In a question, check whether the answer would be he or him: he called, so use who.