Master Relative Pronouns: Who, Whom, Which, That, Whose

Introduction

Have you ever been unsure whether to say “the person who called” or “the person whom called”? Do you wonder when to use “which” instead of “that”? You’re not alone! Mastering relative pronouns is a key step to sounding more fluent and writing more clearly in English. This guide will make these small but powerful words easy to understand and use correctly.

What Are Relative Pronouns?

A relative pronoun is a word like who, whom, which, that, or whose. It connects a clause (a group of words with a subject and verb) to a noun or pronoun. Think of it as a bridge that links extra information back to the person or thing you are talking about. The clause it introduces is called a relative clause.

Rules

1. Use “who” and “whom” for people. “Who” is used as the subject of the clause, and “whom” is used as the object (though “who” is often used informally in both cases).
2. Use “which” for animals and things. It is used in both subject and object positions.
3. Use “that” for people, animals, and things. It is often used in defining relative clauses (clauses essential to the sentence’s meaning).
4. Use “whose” to show possession. It can be used for people, animals, and things to mean “of whom” or “of which.”
5. Remember the comma rule with “which.” Clauses starting with “which” that add extra, non-essential information are usually set off with commas. Clauses with “that” defining essential information do not use commas.

How to Use It

Follow these steps to choose the right relative pronoun:

1. Identify the noun you are describing. Is it a person, an animal, or a thing?
2. Decide if the information is essential or extra. Is the clause necessary to understand which specific noun you mean? If yes, it’s a defining clause. If no, it’s a non-defining clause (adds bonus information).
3. Choose your pronoun based on the rules.
   • Person + defining clause = who/that (subject) or whom/that (object).
   • Person + non-defining clause = who or whom (never “that”).
   • Thing/Animal + defining clause = that or which.
   • Thing/Animal + non-defining clause = which (always with commas).
   • Possession for any = whose.
4. Check the pronoun’s job in its own clause. If it is doing the action, use a subject pronoun (who, which, that). If it is receiving the action, you can use an object pronoun (whom, which, that).

Examples in Sentences

• The woman who lives next door is a doctor.
• She is someone whom I admire greatly.
• The book which is on the table is mine.
• This is the house that Jack built.
• The student whose project won the prize was very happy.
• My car, which is ten years old, still runs perfectly.
• I have a friend who can speak five languages.
• The cake that you baked was delicious.
• That’s the actor whose latest film was a huge success.
• The company, which was founded in 1995, is now a global leader.
• I thanked the man who/that helped me.
• These are the keys that you were looking for.

Common Mistakes

Let’s look at some frequent errors and how to fix them.

1. Using “which” instead of “that” for essential information.
❌ The movie which we saw yesterday was exciting.
✅ The movie that we saw yesterday was exciting. (Defining which movie.)

2. Using “that” in non-defining clauses.
❌ My brother, that lives in Berlin, is visiting.
✅ My brother, who lives in Berlin, is visiting. (Extra information, use commas and “who.”)

3. Confusing “who” and “whom.”
❌ The person whom called didn’t leave a message. (“Whom” cannot be the subject.)
✅ The person who called didn’t leave a message.

4. Forgetting the possessive “whose” for things.
❌ I live in a house of which the roof is red.
✅ I live in a house whose roof is red. (More natural in modern English.)

5. Omitting the pronoun when it’s the object.
❌ The man ∅ I met him yesterday was friendly. (Incorrect double object)
✅ The man who/that/∅ I met yesterday was friendly. (The pronoun can be omitted here because it is the object.)

Quick Summary

• Who/Whom: For people. Use “who” as subject, “whom” as object (formal).
• Which: For animals and things. Often used with commas for extra information.
• That: For people, animals, and things in defining clauses (no commas).
• Whose: Shows possession for people, animals, and things.
• Comma Rule: Use commas with non-defining clauses (usually with “which” or “who”). No commas with defining clauses (often with “that”).

Practice Exercises

Choose the correct relative pronoun (who, whom, which, that, whose) to fill in the blanks. Some sentences may have more than one correct answer!

1. The artist __________ painted this portrait is famous.
2. This is the restaurant __________ we had our first date.
3. My laptop, __________ I bought last year, has stopped working.
4. She is the scientist __________ discovery changed medicine.
5. To __________ did you give the report?

Answers:
1. who/that (subject for a person)
2. that/which (object for a thing in a defining clause)
3. which (non-defining clause about a thing, needs commas)
4. whose (possession)
5. whom (object of the preposition “to” in a question—formal)

Conclusion

Relative pronouns are the helpful connectors that make our sentences richer and more precise. By remembering the simple rules about people, things, essential and extra information, you can use who, whom, which, that, and whose with confidence. Keep practicing, and soon it will become second nature!

FAQ

Q1: Is it ever okay to use “which” without a comma?
A: Yes, but only in defining relative clauses. For example: “The car which is parked illegally will be towed.” Here, “which is parked illegally” tells us which specific car you mean. However, in American English, “that” is more common in defining clauses: “The car that is parked illegally…” In British English, “which” is more accepted in this context.

Q2: Can I just avoid using “whom” altogether?
A: In everyday spoken English, many people use “who” for both subject and object. For example, “Who did you invite?” is very common. However, in formal writing (academic papers, official documents), it is better to use “whom” when it is the object, especially after a preposition (“to whom,” “for whom”). Knowing the rule helps you make the right choice for the situation.

Q3: What’s the difference between “that” and “which”? The main rule.
A: The simplest rule is this: If the clause is essential to identify the noun (a defining clause), use that (or “who” for people). If the clause just adds extra, non-essential information (a non-defining clause), use which (or “who” for people) and put commas around it. Example: “My bike that has a flat tire is in the garage.” (I have more than one bike; this identifies the specific one.) vs. “My bike, which has a flat tire, is in the garage.” (I have one bike, and I’m adding info about it.)

Q4: Can “whose” be used for objects and places?
A: Yes, absolutely! While “whose” often refers to people, it is perfectly correct and very natural to use it for animals, objects, companies, and places to avoid awkward phrases like “of which.” For example: “We visited a city whose history spans a thousand years.” or “The company whose logo is a green leaf is very eco-friendly.”