Relative Clauses: Who, Which, That – Explained

Relative clauses are essential for adding detail and complexity to your sentences. They allow you to provide extra information about nouns, making your writing more precise and engaging. Mastering the use of relative pronouns like who, which, and that is crucial for clear and effective communication in English. This comprehensive guide will break down the rules and nuances of relative clauses, offering numerous examples and exercises to help you achieve fluency. Whether you’re a beginner or an advanced learner, this article will provide you with the tools and knowledge you need to confidently use relative clauses in your everyday speech and writing.

Table of Contents

• Definition of Relative Clauses
• Structural Breakdown
• Types of Relative Clauses
  • Defining Relative Clauses
  • Non-Defining Relative Clauses
• Examples of Relative Clauses
  • Examples with “Who”
  • Examples with “Which”
  • Examples with “That”
  • Defining Relative Clause Examples
  • Non-Defining Relative Clause Examples
• Usage Rules
  • Rules for Using “Who”
  • Rules for Using “Which”
  • Rules for Using “That”
  • Omitting Relative Pronouns
• Common Mistakes
• Practice Exercises
  • Exercise 1: Choosing the Correct Relative Pronoun
  • Exercise 2: Identifying Defining and Non-Defining Clauses
  • Exercise 3: Combining Sentences with Relative Clauses
• Advanced Topics
• FAQ
• Conclusion

Definition of Relative Clauses

A relative clause is a type of subordinate clause that modifies a noun or noun phrase. It provides additional information about the noun it modifies, also known as the antecedent. Relative clauses begin with a relative pronoun (who, which, that, whom, whose) or a relative adverb (where, when, why). They are essential for adding detail and specificity to sentences, allowing for more concise and descriptive writing. Understanding relative clauses is crucial for both reading comprehension and effective communication in English.

Relative clauses function as adjectives, describing or identifying the noun they modify. Consider the sentence, “The book that I borrowed from the library is very interesting.” In this case, “that I borrowed from the library” is the relative clause, and it modifies the noun “book.” Without the relative clause, we would only know that “the book is very interesting,” but the relative clause specifies *which* book we’re talking about.

Structural Breakdown

The basic structure of a relative clause involves a relative pronoun or adverb followed by a subject and a verb (though the subject can sometimes be omitted). The relative pronoun connects the clause to the main clause and refers back to the antecedent.

Here’s a breakdown of the key components:

• Antecedent: The noun or noun phrase that the relative clause modifies.
• Relative Pronoun/Adverb: Who, which, that, whom, whose, where, when, why. This word introduces the relative clause and relates it to the antecedent.
• Subject (Optional): The subject of the relative clause. Sometimes, the relative pronoun acts as the subject.
• Verb: The action or state of being in the relative clause.
• Additional Information: Any extra details that further describe the antecedent.

Let’s examine a few examples to illustrate this structure:

• “The man who helped me is a doctor.” (Antecedent: man; Relative Pronoun: who; Verb: helped)
• “The car that I bought is red.” (Antecedent: car; Relative Pronoun: that; Subject: I; Verb: bought)
• “The house where I live is old.” (Antecedent: house; Relative Adverb: where; Subject: I; Verb: live)

Notice how the relative clause always follows the noun it modifies. This placement is crucial for maintaining clarity and avoiding ambiguity.

The relative pronoun acts as a bridge, connecting the main clause and the relative clause seamlessly.

Types of Relative Clauses

There are two main types of relative clauses: defining (or restrictive) and non-defining (or non-restrictive). These types differ in their function and punctuation.

Defining Relative Clauses

Defining relative clauses provide essential information that identifies or restricts the noun they modify. They are necessary for understanding which specific noun is being referred to. These clauses are not set off by commas because they are integral to the meaning of the sentence. If you remove a defining relative clause, the meaning of the sentence will change significantly or become unclear. They are also called restrictive relative clauses.

For example, “The book that I ordered online arrived today.” The clause “that I ordered online” is essential because it tells us which book arrived – specifically, the one the speaker ordered online. Without this clause, we wouldn’t know which book is being discussed.

Non-Defining Relative Clauses

Non-defining relative clauses provide extra, non-essential information about the noun they modify. They add detail but do not identify or restrict the noun. These clauses are always set off by commas because they are not crucial to the core meaning of the sentence. Removing a non-defining relative clause does not change the basic meaning of the sentence, although it may remove some interesting or helpful details. They are also called non-restrictive relative clauses.

For example, “My sister, who lives in London, is a doctor.” The clause “who lives in London” provides extra information about the speaker’s sister, but it’s not essential for identifying her. We already know who the speaker is talking about – their sister. The commas indicate that this information is additional and not critical to understanding the main point.

Examples of Relative Clauses

Understanding the different types of relative clauses requires seeing them in action. The following sections provide extensive examples of relative clauses using who, which, and that, as well as examples of defining and non-defining clauses.

Examples with “Who”

The relative pronoun who is used to refer to people. It can be used in both defining and non-defining relative clauses.

The following table provides examples of relative clauses using ‘who’ to modify a noun, demonstrating its usage in various contexts.

Sentence	Type of Clause
The woman who teaches my class is very knowledgeable.	Defining
My brother, who is a talented musician, is releasing an album.	Non-Defining
The students who study diligently usually succeed.	Defining
My neighbor, who is always cheerful, brightens everyone’s day.	Non-Defining
The artist who painted this masterpiece is world-renowned.	Defining
My grandmother, who is 90 years old, still enjoys gardening.	Non-Defining
The employee who consistently exceeds expectations will get a promotion.	Defining
My colleague, who is an expert in data analysis, presented the findings.	Non-Defining
The chef who created this dish is a culinary genius.	Defining
My best friend, who I’ve known since childhood, is getting married.	Non-Defining
The doctor who treated me was very kind and professional.	Defining
My aunt, who is a history professor, loves to travel.	Non-Defining
The athlete who won the gold medal trained for years.	Defining
My cousin, who is fluent in three languages, works as a translator.	Non-Defining
The teacher who inspired me the most was my high school English teacher.	Defining
My boss, who is very supportive, always encourages us to learn.	Non-Defining
The scientist who discovered the cure received a Nobel Prize.	Defining
My neighbor, who is a retired engineer, enjoys building model airplanes.	Non-Defining
The author who wrote that book is giving a lecture tonight.	Defining
My sister, who is a talented photographer, is having an exhibition.	Non-Defining
The person who called earlier didn’t leave a message.	Defining
The guide, who knew the mountain well, led us safely.	Non-Defining
The student who asks the most questions learns the most.	Defining
My father, who enjoys playing golf, watches it on TV every weekend.	Non-Defining
The lawyer who defended him was highly skilled.	Defining

Examples with “Which”

The relative pronoun which is used to refer to things or animals. It is typically used in non-defining relative clauses but can sometimes be used in defining relative clauses (though that is often preferred in defining clauses).

Below is a collection of examples demonstrating the use of ‘which’ in relative clauses, showcasing its application in referring to objects, animals, or situations.

Sentence	Type of Clause
The car, which is parked outside, belongs to my brother.	Non-Defining
The book which I borrowed is very interesting.	Defining
My house, which is over 100 years old, needs some repairs.	Non-Defining
The dog, which is a golden retriever, loves to play fetch.	Non-Defining
The movie which won the Oscar was directed by a famous director.	Defining
The restaurant, which is known for its seafood, is always crowded.	Non-Defining
The laptop which I use for work is very reliable.	Defining
The park, which is near my house, is a great place to relax.	Non-Defining
The project which we completed was a great success.	Defining
The museum, which features modern art, is worth visiting.	Non-Defining
The phone which I bought recently has a great camera.	Defining
The garden, which is full of flowers, is my favorite place.	Non-Defining
The cake which she baked was delicious.	Defining
The city, which is famous for its architecture, attracts many tourists.	Non-Defining
The song which they played at the party was very catchy.	Defining
The lake, which is surrounded by mountains, is incredibly scenic.	Non-Defining
The painting which he created is now in a gallery.	Defining
The building, which is the tallest in the city, has a great view.	Non-Defining
The course which I’m taking is very challenging.	Defining
The island, which is known for its beaches, is a popular destination.	Non-Defining
The article which I read yesterday was very informative.	Defining
The forest, which is home to many species, is protected by the government.	Non-Defining
The equipment which they use is very advanced.	Defining
The river, which is the longest in the country, is used for transportation.	Non-Defining
The experiment which they conducted was very successful.	Defining

Examples with “That”

The relative pronoun that can refer to people, things, or animals. It is primarily used in defining relative clauses. While it can sometimes be used in non-defining clauses, this is less common and generally considered less formal.

The subsequent table offers a range of sentences employing ‘that’ in relative clauses, illustrating its versatility in referring to both people and objects within defining contexts.

Sentence	Type of Clause
The book that I borrowed from the library is very interesting.	Defining
The man that helped me was very kind.	Defining
The car that I bought is red.	Defining
The movie that we watched last night was amazing.	Defining
The song that is playing on the radio is my favorite.	Defining
The teacher that I had last year was excellent.	Defining
The phone that I want is very expensive.	Defining
The house that they built is very modern.	Defining
The computer that I use for work is very reliable.	Defining
The food that she cooked was delicious.	Defining
The project that we are working on is very challenging.	Defining
The shoes that I bought are very comfortable.	Defining
The game that they are playing is very exciting.	Defining
The person that called earlier didn’t leave a message.	Defining
The information that he provided was very helpful.	Defining
The course that I am taking is very informative.	Defining
The problem that we are facing is very complex.	Defining
The solution that they found was very creative.	Defining
The idea that he suggested was very innovative.	Defining
The question that she asked was very insightful.	Defining
The reason that he gave was not convincing.	Defining
The place that we visited was very beautiful.	Defining
The job that I applied for is very competitive.	Defining
The company that she works for is very successful.	Defining
The event that we attended was very enjoyable.	Defining

Defining Relative Clause Examples

Defining relative clauses are crucial for specifying which noun is being discussed. They provide essential information and are not set off by commas.

Below is a table containing sentences that feature Defining Relative Clauses. These clauses are critical to the meaning of the sentence and cannot be removed without altering the core information.

Sentence
The student who studies hard usually gets good grades.
The book that I recommended is now a bestseller.
The restaurant that serves the best pizza is always crowded.
The car that I want to buy is too expensive.
The person who called didn’t leave a message.
The movie that we saw last night was terrifying.
The song that is playing on the radio is my favorite.
The teacher who inspires me the most is Mrs. Johnson.
The phone that I dropped is now broken.
The house that they built is very modern and eco-friendly.
The computer that I use for gaming is very powerful.
The food that she cooked for dinner was delicious.
The project that we are working on is due next week.
The shoes that I bought online didn’t fit.
The game that they are playing is a lot of fun.
The information that he provided was very helpful.
The course that I am taking is very challenging.
The problem that we are facing is quite complex.
The solution that they found was surprisingly simple.
The idea that he suggested was truly innovative.
The question that she asked was very insightful.
The reason that he gave wasn’t very convincing.
The place that we visited was incredibly beautiful.
The job that I applied for is extremely competitive.
The company that she works for is highly successful.

Non-Defining Relative Clause Examples

Non-defining relative clauses add extra information that is not essential to the meaning of the sentence. They are always set off by commas.

The table below illustrates Non-Defining Relative Clauses. These clauses provide additional details that enrich the sentence but can be removed without changing the sentence’s fundamental meaning.

Sentence
My sister, who lives in London, is a doctor.
The Eiffel Tower, which is a famous landmark, attracts millions of tourists.
My car, which is quite old, still runs very well.
My dog, who loves to play fetch, is a golden retriever.
The movie, which won several awards, was directed by Christopher Nolan.
The restaurant, which is known for its seafood, is located downtown.
My laptop, which I bought last year, is very reliable.
The park, which is near my house, is a great place to relax.
The project, which was very challenging, was finally completed.
The museum, which features modern art, is worth visiting.
My phone, which I just bought, has a great camera.
The garden, which is full of colorful flowers, is my favorite place.
The cake, which she baked for my birthday, was delicious.
The city, which is famous for its architecture, attracts many tourists.
The song, which they played at the party, was very catchy.
The lake, which is surrounded by mountains, is incredibly scenic.
The painting, which he created last year, is now in a gallery.
The building, which is the tallest in the city, has a great view.
The course, which I’m taking online, is very informative.
The island, which is known for its beautiful beaches, is a popular destination.
The article, which I read yesterday, was very insightful.
The forest, which is home to many rare species, is protected by the government.
The equipment, which they use in the lab, is very advanced.
The river, which is the longest in the country, is used for transportation.
The experiment, which they conducted, was considered a success.

Usage Rules

Using relative pronouns correctly is essential for clear and grammatically sound writing. Each relative pronoun has specific rules governing its use.

Rules for Using “Who”

• Use who to refer to people. This is the most fundamental rule.
• Who can be used in both defining and non-defining relative clauses.
• In non-defining clauses, who is always preceded by a comma.
• Avoid using that to refer to people in non-defining clauses.

Example: “The teacher who inspired me the most was Mr. Anderson.” (Defining)
“My mother, who is a talented artist, loves to paint landscapes.” (Non-Defining)

Rules for Using “Which”

• Use which to refer to things or animals.
• Which is typically used in non-defining relative clauses.
• In non-defining clauses, which is always preceded by a comma.
• While which can be used in defining clauses, that is often preferred, especially in American English.

Example: “The car, which is parked outside, belongs to my dad.” (Non-Defining)
“The book that/which I borrowed from the library is very interesting.” (Defining – that is preferred)

Rules for Using “That”

• Use that to refer to people, things, or animals.
• That is primarily used in defining relative clauses.
• Do not use a comma before that.
• That is generally avoided in non-defining relative clauses. Use who or which instead.

Example: “The house that I bought is very old.” (Defining)
Incorrect: “My house, that is very old, needs repairs.” (Use which instead)

Omitting Relative Pronouns

In certain cases, the relative pronoun can be omitted from a defining relative clause. This is possible when the relative pronoun is the object of the verb in the relative clause.

When the relative pronoun is the subject of the relative clause, it cannot be omitted.

For example: “The book that I read was fascinating” can be written as “The book I read was fascinating” because ‘that’ is the object of the verb ‘read’. However, in the sentence “The book that is on the table is mine”, ‘that’ cannot be omitted because it is the subject of the verb ‘is’.

Common Mistakes

Several common mistakes can occur when using relative clauses. Being aware of these errors can help you avoid them.

Incorrect	Correct	Explanation
The woman, that helped me, is a doctor.	The woman who helped me is a doctor. / The woman that helped me is a doctor.	That is generally not used with commas to introduce non-defining relative clauses when referring to people.
The car who is parked outside is mine.	The car which is parked outside is mine.	Who is used to refer to people, not objects.
My sister which lives in London is a doctor.	My sister, who lives in London, is a doctor.	Non-defining relative clauses require commas. Which is used for things, who is used for people.
The book I read, was very interesting.	The book I read was very interesting.	Defining relative clauses are not set off by commas.
The dog, that I saw, was friendly.	The dog that I saw was friendly. / The dog which I saw was friendly.	‘That’ or ‘which’ are appropriate; commas are not appropriate in defining relative clauses.
The house, which I live, is old.	The house where I live is old.	Use ‘where’ to refer to a place as the location of an action.
She is the person whom I think is the best candidate.	She is the person who I think is the best candidate.	‘Whom’ is becoming less common, and ‘who’ can often be used instead, especially in informal contexts.
The reason why he left, was never explained.	The reason he left was never explained.	Avoid using a comma between the main clause and the relative clause when the relative pronoun is omitted.
The book which’s cover is torn is old.	The book whose cover is torn is old.	Use ‘whose’ to show possession; ‘which’s’ is generally not used.
The teacher, that I like, is leaving.	The teacher that I like is leaving. / The teacher whom I like is leaving.	In defining relative clauses, ‘that’ is preferred; commas are not appropriate.

Practice Exercises

Test your understanding of relative clauses with the following exercises.

Exercise 1: Choosing the Correct Relative Pronoun

Fill in the blanks with the correct relative pronoun (who, which, or that).

Question	Answer
The man ______ I saw yesterday is my uncle.	that/who
The car, ______ is parked outside, is mine.	which
The book ______ I am reading is very interesting.	that/which
The woman ______ teaches my class is very knowledgeable.	who
The house ______ I grew up in is still standing.	that/which
The dog, ______ is a golden retriever, loves to play fetch.	which
The movie ______ we watched last night was amazing.	that/which
The song ______ is playing on the radio is my favorite.	that/which
The teacher ______ inspired me the most was Mr. Anderson.	who
The phone ______ I want is very expensive.	that/which

Exercise 2: Identifying Defining and Non-Defining Clauses

Identify whether the relative clause in each sentence is defining (D) or non-defining (ND).

Question	Answer
The book that I borrowed from the library is overdue.	D
My sister, who lives in London, is a doctor.	ND
The car which is parked outside is blocking my driveway.	D
The Eiffel Tower, which is a famous landmark, attracts many tourists.	ND
The student who studies hard usually gets good grades.	D
My house, which is over 100 years old, needs some repairs.	ND
The movie that won the Oscar was directed by a famous director.	D
My dog, who loves to play fetch, is a golden retriever.	ND
The restaurant that serves the best pizza is always crowded.	D
My laptop, which I bought last year, is very reliable.	ND

Exercise 3: Combining Sentences with Relative Clauses

Combine the following pairs of sentences into one sentence using a relative clause.

Question	Answer
The man is my neighbor. He helped me fix my car.	The man who helped me fix my car is my neighbor.
The book is on the table. I borrowed it from the library.	The book that I borrowed from the library is on the table.
My sister lives in London. She is a doctor.	My sister, who lives in London, is a doctor.
The car is parked outside. It belongs to my brother.	The car, which is parked outside, belongs to my brother.
The movie won several awards. It was directed by Christopher Nolan.	The movie, which won several awards, was directed by Christopher Nolan.
The student studies hard. He usually gets good grades.	The student who studies hard usually gets good grades.
The house is over 100 years old. It needs needs some repairs.	The house, which is over 100 years old, needs some repairs.

Advanced Topics

For advanced learners, understanding more complex aspects of relative clauses can further enhance your writing and comprehension skills. These include topics such as using relative adverbs (where, when, why), reduced relative clauses, and the use of whom.

Relative Adverbs: Relative adverbs (where, when, why) can introduce relative clauses, replacing a preposition + which. For example, “The house in which I live is old” can be rewritten as “The house where I live is old.”

Reduced Relative Clauses: A reduced relative clause is a relative clause that has been shortened by omitting the relative pronoun and auxiliary verb. For example, “The book that is written by John Grisham is a thriller” can be reduced to “The book written by John Grisham is a thriller.”

The Use of Whom: The relative pronoun ‘whom’ is used to refer to the object of a verb or preposition. While less common in modern English, particularly in informal contexts, it’s important to recognize its proper usage. For example, “The man to whom I spoke was very helpful.”

FAQ

Conclusion

Mastering relative clauses is a significant step toward improving your English writing and speaking skills. By understanding the different types of relative clauses, the correct usage of relative pronouns, and common mistakes to avoid, you can add depth and precision to your communication.

Continue practicing with the exercises and examples provided in this guide, and you’ll soon find yourself using relative clauses with confidence and ease. Remember, effective communication is all about clarity and accuracy, and relative clauses are a powerful tool for achieving just that.