Most Common Grammar Mistakes - Who or Whom?

Who or whom?

Here’s a tricky one: “Who/whom did he see at the party?”

Here’s what you need to know:

Who = subject pronoun
Whom = object pronoun

So, to get the answer, change the question to a statement: “He did see whom at the party.”

Whom is an object, so that is the answer  .

Question: “Who/whom ate all the cookies?” Statement: “Who ate all the cookies.”