Who vs. Whom & Who’s vs. Whose
Put simply, who is the subject and whom is the object of a sentence. There is a very easy trick to use to know you’re always using the right one. Rework the sentence using he or him, and that will give you your answer: who = he, whom = him.
Who/whom wrote the article? He wrote it; therefore, it’s who.
Who/whom was the article about? It was about him; therefore it’s whom.
To who/whom is the article being delivered? It’s delivered to him; therefore it’s whom.
This one is almost always used incorrectly. However, it’s a very easy distinction. Who’s is a contraction for who is or who has. Whose is used to show possession. Whose as a possessive is often confusing because possessives usually use an apostrophe + s (Mike’s shoes, Cindy’s dress, Brad’s party). But, in the case of whose, there is no apostrophe.
Who’s going to the party tonight?
Whose party is it?
Who’s been to one of Brad’s parties before?
Who’s going as whose guest?
Simple enough, right?