Who and Whom
WHO is used when we refer to the subject of a sentence.
WHOM is used when we refer to the object of a verb or preposition.
If you can replace the word with he or she then use who.
- Who is going to the movies tonight?
- She is going to the movies tonight.
‘She’ (or he) works here so you use ‘who’.
If you can replace it with him or her use whom.
- The soccer teams is coached by whom?
- By whom is the soccer team coached?
- The soccer team is coached by her.