We have all run into this problem of not knowing when to use “who” and when to use “whom”. Who and whom are both pronouns. How to use them depends on what you are referring to in the sentence. If you are referring to the subject of the sentence you use “who”. If you are referring to the object in a sentence or clause you would use “whom”.
It can seem confusing to think about subject and object but it really isn’t so difficult if you break it down. The subject is usually the person in the sentence that is doing something and the object is the thing that the subject is doing something to.
Sample sentence: Mary kicked the ball.
Mary is the subject and the ball is the object.
So if you were going to add who or whom to this sentence you would say “Who kicked the ball?” because “who” refers to the subject which is Mary.
If it helps you can think of the pronouns as replacing the object and subject. So in the sentence above. Mary is the subject and when you put “Who” in the place of “Mary” you are replacing the subject. We will give you a few more examples. Remember that “who” and “whom” are interrogative pronouns. They ask about the subject or object.
- Jim ate the sandwich?
Who ate the sandwich?
- Jim had a sandwich with Mary.
Whom did Jim have a sandwich with?
- Jeremy went to the store.
Who went to the store?
- Jeremy went to the store with JoAnn.
With whom did Jeremy go to the store?
Who and whom can also be used in statements. Just remember that they replace a subject and/or and object. One rule of thumb is to remember that “whom” is always to be used after a preposition. English can be tricky in this way but if you just remember the few key points it can make the rules of grammar usage much easier.