Grammar Tips: A Guide to Relative Pronouns
  • 5-minute read
  • 4th June 2023

Grammar Tips: A Guide to Relative Pronouns

The definition of a pronoun seems straightforward: a word used as a substitute for a noun. However, many types of pronouns exist because the pronoun is a versatile part of speech. We use relative pronouns to introduce relative clauses. The most common relative pronouns in English are which, that, who, and whom.

What Is a Relative Clause?

A relative clause gives additional information about a specific noun (which is called the antecedent of the relative clause). These clauses are also known as adjective clauses because, like adjectives, they describe or modify a noun. Restrictive and nonrestrictive are the two types of types of relative clauses – which leads us into our first set of relative pronouns…

Which vs. That

Which and that are not interchangeable. To determine the correct one to use, you first need to determine whether your relative clause is restrictive or nonrestrictive. A restrictive clause provides essential identifying information about its antecedent; without a restrictive clause, the meaning of the sentence changes. A nonrestrictive clause provides additional information that is nice to have but can be removed without affecting meaning.

Take a look at these examples, in which the relative clause is highlighted:

The chocolate that I love is on sale right now.

That chocolate, which I love, is on sale right now.

Though similar, these sentences convey slightly different information. In the first, the speaker is saying that their favorite chocolate, specifically, is on sale. In the second, the speaker is indicating that a type of chocolate is on sale, and they happen to like it. The first sentence contains a restrictive clause, and the second sentence contains a nonrestrictive clause.

Restrictive clauses should start with that, and nonrestrictive clauses should start with which. In other words, if the information is essential, use that; if it’s just nice to know, use which.

In addition to grammar considerations, you should also note that punctuation is different in the two types of clauses. As you can see in the last set of examples, nonrestrictive clauses (those that use which) are always set off by commas. Restrictive clauses (those that use that) are not. Be careful about your punctuation; forgetting your commas when using nonrestrictive clauses is a common error.

Who vs. Whom

When deciding between who and whom, you don’t need to worry about restrictive and nonrestrictive clauses. Rather, you need to determine whether the pronoun is the subject or the object of the clause. If it’s the subject, use who; if it’s the object, use whom.

The subject is the person or thing that is doing the action indicated by the verb. The object is the person or thing that the action is done to or that is affected by the action. To determine the difference, it’s helpful to focus on the clause itself:

The man who works at the candy store is very nice.

In the above example, the man is doing the work at the candy store, and who is taking the place of man in the relative clause who works at the candy store. Because who is acting as the subject of that clause, it’s the correct choice. Now, consider this:

He is a person whom I admire very much.

Here, the subject of the relative clause whom I admire very much is I, and the object of the action (admire) is whom, which is standing in for he. So whom is the correct choice.

Whom can also be the object of a preposition. If you see a preposition (to, with, for, and at are common examples), use whom instead of who:

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Ask not for whom the bell tolls.

She is the woman to whom I sent a letter.

Other Relative Pronouns

You can also use what, whichever, whoever, whomever, and whatever as relative pronouns, but they function a little differently. Their relative clauses don’t normally follow a noun. Instead, the whole clause functions as the subject or object of a sentence.

What he did today was record-breaking.

In this game, whoever gets rid of their cards first is the winner.

We will do whatever we can to stop this.


Can I omit the relative pronoun in a clause?

Sometimes, yes. You can omit whom and that only if they’re the object of the clause. Generally, however, a subject and verb are in the relative clause in these instances. For example:

The woman whom they listened to was a good speaker.

In the above relative clause, they is the subject, listened is the verb, and whom is the object. We can remove whom and get:

The woman they listened to was a good speaker.

The following example is similar:

The house that Jack built was made of bricks.

In the relative clause (in bold), Jack is the subject, built is the verb, and that is the object. We can remove that, giving us:

The house Jack built was made of bricks.

Do we need to consider regional differences when using relative pronouns?

Yes! The which vs. that rule above applies to US English. In the UK, which is used for nonrestrictive clauses, but either that or which can be used for restrictive clauses.

Are there any rules for using who vs. that?

Strictly speaking, yes. The rule, however, has some ambiguity. In general, we use who to refer to people and that to refer to inanimate objects. But matters get sticky when your antecedent is neither a person nor a thing. Pets and other animals fit into this category (the average cat owner, for instance, thinks of their cat as a who rather than a that, and the cat usually agrees). And as computer science continues to evolve, society will need to decide what to call advanced AIs and ever more sophisticated robots.

In Conclusion

Deciding when to use that instead of which or who instead of whom can be tricky. Take a little time to break the sentence down, figure out what type of clause you’re dealing with, and determine whether the pronoun functions as a subject or an object – you’ll be one step closer to getting your pronouns perfect.

Still a little uncertain? Our Proofed editors can help you perfect your writing. Give us a try for free. Want more writing tips? Check out our Writing Tips and Academic Writing Tips blogs.

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