Who vs. Whom

Just a short post today, but on another thing people frequently misuse.

Who refers to the subject of a sentence.
Whom refers to the object of a verb or proposition.

Cheat sheet: 

If you can replace the word with he or she,
use who

If you can replace the word with him or her,
use whom.

WHO

Who would like to borrow a book?
(She would like to borrow a book.)

Who wants a piece of cake?
(He wants a piece of cake.)

Who made the potato salad?
(They made the potato salad.)

WHOM

To whom was the parcel sent to?
(The parcel was sent to her.)

Whom does the dog belong to?
(The dog belongs to him.)

Got another grammar question? 
Contact me and I'll add it to the blog.