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 friendly guide will make these useful little 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.
2. Use “which” for animals and things. It is used in both defining (essential) and non-defining (extra information) clauses.
3. Use “that” for people, animals, and things. It is mostly used in defining relative clauses (information that is 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. Non-defining clauses add extra information and are separated by commas. You cannot use “that” in these clauses.

How to Use It

Let’s break down how to choose the right relative pronoun step-by-step.

Step 1: Identify What You Are Describing

Is it a person, an animal, or a thing? This is your first clue.

• Person → who, whom, whose, that
• Animal/Thing → which, that, whose

Step 2: Decide If the Information Is Essential

Is the clause necessary to identify which person or thing you mean? If you remove it, does the sentence still mean the same thing?

• Essential (Defining Clause): No commas. You can use “that,” “who,” or “which.”
  Example: The book that you lent me is fantastic. (We need “that you lent me” to know which book.)
• Extra Info (Non-Defining Clause): Use commas. Use “who,” “whom,” or “which.” Never use “that.”
  Example: My car, which is ten years old, still runs well. (We know which car—”my car.” The clause just adds extra detail.)

Step 3: Check the Pronoun’s Job in the Clause

Is the pronoun doing the action (subject), receiving the action (object), or showing possession?

• Subject: Use who (people) or which/that (animals/things).
  The woman who lives next door is a doctor.
• Object: Use whom (formal), who (informal), or which/that (animals/things). You can often omit the pronoun in defining clauses.
  The friend (whom) I visited is moving away.
• Possession: Always use whose.
  That’s the artist whose paintings we admired.

Examples in Sentences

• The student who studied hardest got the best grade.
• She is the candidate whom we interviewed yesterday.
• My laptop, which I bought last year, needs an update.
• This is the house that Jack built.
• I have a friend whose brother is a famous musician.
• The book that is on the table is mine.
• Our manager, who is very supportive, approved my leave.
• The movie (that) we saw last night was thrilling.
• That’s the dog whose owner is looking for it.
• The company, which was founded in 1995, is expanding.
• Anyone who finishes early can leave.
• The keys that you lost were in the kitchen.

Common Mistakes

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

1. Using “which” instead of “that” in a defining clause

❌ The car which I want is red.
✅ The car that I want is red. (Or simply: The car I want is red.)
Tip: In defining clauses about things, “that” is often preferred, especially in American English.

2. Using “that” in a non-defining clause

❌ My sister, that lives in Paris, is visiting.
✅ My sister, who lives in Paris, is visiting.
Tip: Remember the comma rule! If you have commas, you cannot use “that.”

3. Confusing “who” and “whom”

❌ The person who I spoke to was helpful.
✅ The person whom I spoke to was helpful. (Formally correct)
✅ The person who I spoke to was helpful. (Informally acceptable)
Tip: Try substituting “he” (who) or “him” (whom). “I spoke to him.” So, “whom” is formally correct.

4. Using “who’s” instead of “whose”

❌ That’s the man who’s car was stolen.
✅ That’s the man whose car was stolen.
Tip: “Who’s” is a contraction for “who is” or “who has.” “Whose” shows possession.

Quick Summary

• Who/Whom: For people. “Who” is subject, “whom” is object.
• Which: For animals and things. Used with or without commas.
• That: For people, animals, things. Used in defining clauses (no commas).
• Whose: Shows possession for people, animals, and things.
• Commas: Use with “who” or “which” for extra information. Never use “that” after a comma.

Practice Exercises

Choose the correct relative pronoun (who, whom, which, that, whose) to fill in the blank. Sometimes more than one answer is possible!

1. The woman ___ lives next door is a pilot.
2. This is the restaurant ___ we had our first date.
3. My grandfather, ___ is 90, still goes for walks.
4. He’s the player ___ performance amazed everyone.
5. I need a computer ___ can handle video editing.

Answers:
1. who/that (Subject for a person)
2. that/which (Object for a thing in a defining clause; pronoun can also be omitted)
3. who (Subject for a person in a non-defining clause)
4. whose (Shows possession)
5. that/which (Subject for a thing in a defining clause)

Conclusion

Relative pronouns are powerful tools for connecting your ideas smoothly. With a little practice, choosing between who, whom, which, that, and whose will become second nature. Remember the key rules about people vs. things and essential vs. extra information, and you’ll be well on your way to mastering this grammar topic.

FAQ

Is it ever okay to omit a relative pronoun?

Yes! In defining relative clauses where the pronoun is the object (not the subject), you can omit it. For example: “The book (that) you recommended is great.” You cannot omit the pronoun if it is the subject (“The woman who called you…”) or in non-defining clauses (“My boss, who is very kind,…”).

What is the difference between “which” and “that”?

The main difference is the type of clause. “That” is used in defining clauses (information essential to the sentence’s meaning). “Which” can be used in both, but when it’s in a non-defining clause (extra information, set off by commas), you must use “which.” A simple tip: if you can remove the clause without losing the main point, you probably need “which” with commas.

Is “whom” becoming obsolete?

In everyday, informal spoken English, “whom” is used less and less. Many people use “who” for both subject and object. However, “whom” is still required in formal writing and is appreciated in situations where grammar is closely scrutinized. Knowing the rule helps you make the right choice for the context.

Can I use “whose” for things?

Absolutely! While “whose” often refers to people, it is perfectly correct and very useful to use it for animals and things, especially when “of which” sounds awkward. For example: “The company whose profits doubled this year” is much more natural than “The company the profits of which doubled this year.”