In adjective clauses, 'who' is used as the subject, and 'whom' as the object.
How do we know if we should use the subject (who) or object (whom)?
Here are some tricks I use:
Now this trick only works when dealing with sentences. I have another trick for when we get into questions.
Look at the word that follows who/whom. If the word is a verb, then use who. If the word that follows is a noun/pronoun, then use whom.
While not everyone might know or even think about it, word order for the English language is Subject-Verb-Object, also known as SVO. Now pretend that this goes on forever:
SVOSVOSVOSVO…
Example:
I want to know who/whom you love.
Logic used: The word that follows “who/whom” is “you”.
“You” is a pronoun.
It fits into the pattern this way: SVOSVO
Correct: I want to know whom you love.
Example:
I wonder who/whom borrowed the book.
Logic used: The word that follows “who/whom” is “borrowed”.
“Borrowed” is a verb.
It fits into the pattern this way: SVOSVO
Correct: I wonder who borrowed the book.
TRICK #2
But you know what? This could be tricky for some people, so here’s an even simpler way:
Who = she/he (subject)
Whom – her/him (object)
Example:
I want to know who/whom you love.
Ask yourself, what sounds right?
You love he. / You love him.
Correct: I want to know whom you love.
Example:
I wonder who/whom borrowed the book.
Ask yourself, what sounds right?
She borrowed the book. / Her borrowed the book.
Correct: I wonder who borrowed the book. -
Let’s use examples that are in the form of questions:
Example:
Who/whom did you invite to the party?
Ask yourself, which sounds right?
I invited he. / I invited him.
Correct: Whom did you invite to the party?
Example:
Who/whom was the first to step foot on the moon?
Ask yourself, which sounds right?
He was the first. / Him was the first.
Correct: Who was the first to step foot on the moon?
Still having trouble? Well, good news. I don’t think too many people would care or even notice if 'whom' slips out of the language altogether. It doesn't add clarity, or even useful nuance. Using it adds a bit of class, but not using it is not the error it might once have been.
So in the end, who cares?