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Related resource: https://www.engvid.com/who-or-whom/
Quick Reference
"Who" and "whom" are used as question pronouns and relative pronouns.
"Who" is a subject relative pronoun and relates to the subject of a sentence (I/he/she/we/they/you as subject).
"Whom" is an object relative pronoun and relates to the object of a sentence (me/him/her/us/them/you as object).
"Whom" is used with prepositions.
The continued use and relevance of "whom" is debated among linguists and grammarians, and the use of "whom" is not common in most contexts.
If you are reading this, you are probably a student who needs (or wants) to finally learn the difference between "who" and "whom". Or maybe you are someone who is trying to win a bet with a friend as you yell "It's WHO!" and "It's WHOM!" back and forth at one another. In either case, you have come to the right place. This page will teach you the facts, rules, and uses of "who" and "whom" in English.
Before you scroll down for the information you are really here for, it is important to stress three things about the usage of "who" and "whom":
1. Most English speakers use "who" for almost every conversational situation even when, grammatically, they should use "whom." This is because most English speakers simply do not know the formal rules for these two words. This is not really their fault, nor is it a problem in most conversational situations. In reality, due to a gap in formal knowledge, and as a result of years of popular usage, the use of "who" instead of "whom" in most situations has been standardized and accepted by the vast majority of English speakers.
2. While "whom" often sounds formal to the ears of most English speakers, and is considered archaic by others, it is still used in speech by some people--and not just by puritan grammar teachers! As with anything, it is always a good idea to "read the room" and know your audience. With that in mind, it is recommended that you use "who" and "whom" properly in academic and formal professional contexts in particular, especially in writing.
3. There are people who use "who" and "whom" properly not because they want to feel fancy or superior to other people, but because it was how they learned to speak. (I can feel some of you thinking "That's right! They learned how to speak properly!") With that in mind, it is 100% possible to sound natural and unpretentious when using "whom." It is an accepted part of English. Just do not make a big show of using it, and preferably, do not do it with your nose in the air.
With that out of the way, here are the facts.
Fact 1: "Who" and "whom" are pronouns
This means they are placeholders for nouns. In the case of "who" and "whom," they are placeholders for people, and can be used as both question pronouns and relative pronouns.
Question pronouns
Example 1: "Who did this?"
Example 2: "Whom did you see?" (Keep reading to learn why "whom" is technically correct here. However, keep in mind that it is common and accepted to hear "who" in all question forms.)
We use "who" and "whom" as question pronouns when we do not know what or which person or people did something or had something done to them.
Relative pronouns
Example 1: "There are some people who think the crime was staged."
Example 2: "They picked the player whom I wanted."
Relative pronouns relate to (or, if you prefer, refer back to) nouns or pronouns. In the two examples above, "who" relates to "people," and "whom" relates to "the player."
Fact 2: "Who" is a subject relative pronoun
This means it relates to the subject of a sentence. The subject is "the doer," or the person who does the action in a sentence, or who(m) the sentence is about.
Example 1: "Who is Debbie?" "Debbie is the grade 6 student who is always sick."
Debbie is always sick. Debbie is the subject of the sentence. "Who" relates to "Debbie."
Example 2: "They're the ones who came in first place in the boat race."
They came in first place in the boat race. They won the race. They is the subject of the sentence. "Who" relates to "They."
Formal rule: Use "who" when you are relating or referring back to the subject of the sentence.
Grammar hack: If you can ask a question about your sentence, and the answer is a subject pronoun (I/he/she/we/they/you as subject), use "who." In example 1, you can ask "Who is the grade 6 student who is always sick?" and answer with "Debbie. She is the one." In example 2, you can ask "Who came in first place in the boat race?" and answer with "They did. They were the ones."
Another trick you can do is to rephrase the clause or sentence to see if the person or people being referred to are in the subject position, and if they can be replaced with a subject pronoun (I/he/she/we/they/you as subject). For example: "Debbie is always sick. She is always sick." / "They were the ones. They came in first place in the boat race."
Fact 3: "Whom" is an object relative pronoun
This means it relates to the object of a sentence. The object is the person who receives the action in a sentence. It does not refer to "the doer," but to "the receiver."
Example 1: "David wasn't the candidate whom we expected."
David wasn't the candidate we expected. We didn't expect him. We is the subject (or "the doer") of the sentence, and David is the object (or "the receiver") of the sentence. Whom refers back to David in this case.
Example 2: "I've never met the man whom she married."
She married the man. She married him. The man is the object in this case. Whom refers back to the man.
This is also the reason we asked the "Whom did you see?" question in the Fact 1 section above. "I saw someone" is implied here, with "I" as the subject, and the mysterious "someone" as the object.
Formal rule: Use "whom" when you are relating or referring back to the object of the clause or sentence.
Grammar hack 1: If you can ask a question about your sentence, and the answer is an object pronoun (him/her/us/them/you as object), use "whom." In example 1, you can ask "Who didn't you expect?" and answer with "David. We didn't expect him." In example 2, you can ask "Have you ever met the man she married?" and answer with "No. I've never met him."
Just as above, another trick you can do is to rephrase the clause or sentence to see if the person or people being referred to are in the object position. For example: "We didn't expect David. We didn't expect him." / "I've never met the man whom she married. I've never met him."
Grammar hack 2: If the relative pronoun is followed by a noun or pronoun, the relative pronoun is usually "whom." For instance, "the person whom I love," or "the candidate whom they selected."
Fact 4: "Whom" is used with prepositions
Prepositions need objects. For example: on the table, with my friend, for you, against the tide, etc. In the case of "whom," since it is an object relative pronoun, if your preposition needs an object and you have to choose between "who" and "whom," "whom" is considered more grammatically correct. This is a more formal structure, but it is still prevalent in classic literature, and has some contemporary applications. Let's take a look at some examples:
"To whom did you speak?"
"Whom did you speak to?"
"She was the one with whom I studied."
"She was the one whom I studied with."
Yes, it is completely fine to use prepositions at the end of a sentence. Of course, in most modern conversations, most people today would just say "Who did you speak to?" and "She was the one who I studied with" (or "...the one I studied with" with no relative pronoun at all).
It is important to remember that due to the perceived formality of "whom," some questions and sentences sound ridiculous to most people when "whom" is used. For instance, the common question, "Who(m) are you talking about?" could be rephrased as "About whom are you talking?" And really, no one talks like that. A more acceptable way to say this, if you would like to use a more formal tone, might be "To whom are you referring?" Keep standard usage in mind.
Formal rule: Use "whom" as the object of a preposition.
Fact 5: "Whom" is used with relatives clauses which use "of" quantifiers
A common and more relevant construction which uses "whom" after a preposition is the quantifier + "of" + whom construction. This is an extension of Fact 4. Note the examples:
Example 1: "There were ten people in the meeting, two of whom had arrived late."
Example 2: "Twenty of my co-workers, all of whom had bought lottery tickets on Friday, didn't come to work on Monday."
You can use this construction with all types of quantifiers and quantifying phrases. For example: the majority of whom, 25% of whom, half of whom, six of whom, a lot of whom, none of whom, etc. There are not many opportunities to use this construction in everyday conversation, but if it ever comes up, stick with "whom," although "who" is also fine to most ears.
Formal rule: Use "whom" after "of" in quantifying phrases.
Fact 6: "Who" is used with the focus (or "new subject") of a passive voice sentence
In the passive voice, the object of a sentence becomes the subject. Because of this, the rules flip for whether to use "who" or "whom." The person who receives the action, who is now the main focus of the sentence, becomes the subject and must therefore be referred back to by "who." Note the examples:
Active voice: The person whom we picked declined our offer. (We picked the person. We picked him/her/them.)
Passive voice: The person who was picked (by us) declined our offer. (The person was picked. He/She/They were picked by us.)
Here is another similar example:
Active voice: Zaki, whom we had not invited, showed up to the party regardless.
Passive voice: Zaki, who had not been invited (by us), showed up to the party regardless.
Finally, we need to keep in mind that there is more than one way to say something and that it's not always wise to use the passive voice, as it can create needlessly long and complicated sentences. Note the following sentences:
Active: She chose the person with the most years of experience.
Active: The person with the most years of experience was whom she chose.
Passive: The person who had the most years of experience was who was chosen (by her).
Do not forget, however, that if there is a preposition in the passive sentence, you should still technically use "whom."
Active voice: Joe, who impressed us during the interview, took the job.
Passive voice: Joe, whom we were impressed by during the interview, took the job. (Or, "by whom we were impressed.")
Of course, the most important thing is for the sentence to sound natural. Usually, a sentence just sounds better in the active voice.
Conclusion
In the end, keep the 3 points at the top of this article in mind above everything else. Depending on whom you talk to, the use of "whom" is either proper or out of fashion. Keep your audience in mind, and make your own decision about how much importance you want to place on the technical correctness of "who" and "whom" versus what just sounds more natural in everyday English.
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