Relative Clauses: Defining & Non-Defining | Grammar Guide
Relative clauses add extra information to a noun in a sentence. Understanding the difference between defining and non-defining relative clauses is crucial for clear and effective communication.
Defining relative clauses are essential for identifying the noun they modify, while non-defining relative clauses provide additional, non-essential information. This article will explore the structure, usage, and punctuation of both types of relative clauses, providing numerous examples and practice exercises to help you master this important grammar concept.
This is suitable for English language learners of all levels, from intermediate to advanced.
Table of Contents
- Introduction
- Definition of Relative Clauses
- Structural Breakdown
- Types or Categories
- Examples of Relative Clauses
- Usage Rules
- Common Mistakes
- Practice Exercises
- 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, helping to identify or describe it further. Relative clauses are introduced by relative pronouns (who, whom, which, that, whose) or relative adverbs (where, when, why).
Defining Relative Clauses
A defining relative clause (also known as an essential or restrictive relative clause) is necessary to identify the noun it modifies. It provides essential information that limits or defines the noun.
Without the defining relative clause, the meaning of the sentence would be unclear or incomplete. Defining relative clauses are not set off by commas.
Consider the following example: “The book that I borrowed from the library is due next week.” The phrase “that I borrowed from the library” is essential because it tells us which specific book is being discussed. Without it, we wouldn’t know which book the speaker is referring to.
Non-Defining Relative Clauses
A non-defining relative clause (also known as a non-essential or non-restrictive relative clause) provides extra information about a noun, but it is not essential for identifying the noun. The sentence would still make sense without the non-defining relative clause.
Non-defining relative clauses are always set off by commas.
For example: “My sister, who lives in London, is a doctor.” The phrase “who lives in London” provides additional information about the sister, but it’s not essential. We already know who the speaker is talking about (their sister).
Structural Breakdown
Understanding the structure of relative clauses involves recognizing the roles of relative pronouns and adverbs, and how they connect the clause to the main sentence.
Relative Pronouns
Relative pronouns connect the relative clause to the noun it modifies. The choice of relative pronoun depends on the function of the pronoun within the relative clause and whether the noun is a person or thing.
- Who: Used for people, functioning as the subject of the relative clause. Example: “The woman who is speaking is my teacher.”
- Whom: Used for people, functioning as the object of the relative clause. Example: “The man whom I saw yesterday is my neighbor.” (Often, “who” is used instead of “whom” in informal English.)
- Which: Used for things and animals. Example: “The car which I bought is very fast.”
- That: Used for both people and things, often in defining relative clauses. Example: “The movie that I watched last night was amazing.”
- Whose: Used to show possession for both people and things. Example: “The student whose essay won the prize is very talented.”
Relative Adverbs
Relative adverbs introduce relative clauses that modify nouns related to time, place, or reason.
- Where: Used to modify a place. Example: “The restaurant where we had dinner is very expensive.”
- When: Used to modify a time. Example: “The day when I met her was unforgettable.”
- Why: Used to modify a reason. Example: “The reason why I’m late is because of the traffic.”
Omitting Relative Pronouns
In some cases, the relative pronoun can be omitted, particularly in defining relative clauses when the pronoun is the object of the verb in the relative clause. This is common in informal English.
For example: “The book I read was interesting.” (Here, “that” is omitted: “The book that I read was interesting.”)
However, you cannot omit the relative pronoun if it is the subject of the relative clause: “The person who helped me was very kind.” (You cannot omit “who” here.)
Types or Categories
Relative clauses can also be categorized based on their function within the sentence: subject, object, or possessive.
Subject Relative Clauses
In a subject relative clause, the relative pronoun acts as the subject of the verb in the relative clause. The relative pronoun replaces the subject of the clause.
Example: “The dog that barked woke me up.” (“That” is the subject of “barked.”)
Object Relative Clauses
In an object relative clause, the relative pronoun acts as the object of the verb or a preposition in the relative clause. The relative pronoun replaces the object of the clause.
Example: “The movie that I watched was very exciting.” (“That” is the object of “watched.”)
Possessive Relative Clauses
Possessive relative clauses use “whose” to show possession. “Whose” modifies a noun within the relative clause.
Example: “The author whose book I read is coming to our school.” (“Whose” shows that the book belongs to the author.)
Examples of Relative Clauses
Here are extensive examples, organized by type, to illustrate the different uses of relative clauses.
Defining Relative Clause Examples
The following table provides 30 examples of defining relative clauses, illustrating their essential role in identifying the noun they modify. Notice that there are no commas used in these sentences.
| Sentence | Relative Clause | Relative Pronoun/Adverb |
|---|---|---|
| The student who studies hard usually succeeds. | who studies hard | who |
| The book that I ordered arrived today. | that I ordered | that |
| The restaurant where we ate last night was excellent. | where we ate last night | where |
| The car which is parked outside is mine. | which is parked outside | which |
| The person whose wallet was stolen reported it to the police. | whose wallet was stolen | whose |
| The house that Jack built is now for sale. | that Jack built | that |
| The song that she sang was beautiful. | that she sang | that |
| The man who is wearing a hat is my father. | who is wearing a hat | who |
| The movie which won the award was very long. | which won the award | which |
| The city where I grew up is very different now. | where I grew up | where |
| The reason why I am late is the traffic. | why I am late | why |
| The cake that Mary baked was delicious. | that Mary baked | that |
| The woman who teaches English is very patient. | who teaches English | who |
| The computer which I bought is very fast. | which I bought | which |
| The park where I walk my dog is very large. | where I walk my dog | where |
| The student whose project was the best received extra credit. | whose project was the best | whose |
| The book that is on the table is mine. | that is on the table | that |
| The teacher who gave the lecture was very knowledgeable. | who gave the lecture | who |
| The car which I want to buy is very expensive. | which I want to buy | which |
| The house where I live is very old. | where I live | where |
| The reason why I am happy is because of you. | why I am happy | why |
| The dress that she wore was stunning. | that she wore | that |
| The boy who broke the window ran away. | who broke the window | who |
| The game which I played was very addictive. | which I played | which |
| The beach where I swim is very clean. | where I swim | where |
| The artist whose paintings are famous is from Spain. | whose paintings are famous | whose |
| The food that I ate was spicy. | that I ate | that |
| The doctor who treated me was very kind. | who treated me | who |
| The phone which I use is very old. | which I use | which |
| The shop where I buy my clothes is having a sale. | where I buy my clothes | where |
Non-Defining Relative Clause Examples
The following table provides 30 examples of non-defining relative clauses, illustrating how they add extra, non-essential information. Note the use of commas to set off these clauses.
| Sentence | Relative Clause | Relative Pronoun/Adverb |
|---|---|---|
| My mother, who is a teacher, is very patient. | who is a teacher | who |
| The Eiffel Tower, which is in Paris, is a famous landmark. | which is in Paris | which |
| London, where I used to live, is a vibrant city. | where I used to live | where |
| My car, which is very old, still runs well. | which is very old | which |
| Shakespeare, whose plays are world-renowned, was a great writer. | whose plays are world-renowned | whose |
| My brother, who is a doctor, works at the hospital. | who is a doctor | who |
| Rome, which is the capital of Italy, is a beautiful city. | which is the capital of Italy | which |
| Yesterday, when I went to the store, I saw my friend. | when I went to the store | when |
| The cat, which was sleeping on the sofa, woke up. | which was sleeping on the sofa | which |
| My neighbor, whose garden is beautiful, is very friendly. | whose garden is beautiful | whose |
| My aunt, who lives in Canada, is visiting next month. | who lives in Canada | who |
| The Louvre, which houses the Mona Lisa, is a famous museum. | which houses the Mona Lisa | which |
| Paris, where the Eiffel Tower stands, is a romantic city. | where the Eiffel Tower stands | where |
| My bicycle, which I bought last year, is my favorite way to travel. | which I bought last year | which |
| Einstein, whose theory of relativity changed physics, was a brilliant scientist. | whose theory of relativity changed physics | whose |
| My grandfather, who fought in the war, is a hero. | who fought in the war | who |
| Venice, which is known for its canals, is a unique city. | which is known for its canals | which |
| Last summer, when we went to the beach, we had a great time. | when we went to the beach | when |
| The dog, which is a golden retriever, is very friendly. | which is a golden retriever | which |
| My classmate, whose grades are excellent, is applying to Harvard. | whose grades are excellent | whose |
| My best friend, who is a talented musician, is playing a concert. | who is a talented musician | who |
| The Colosseum, which is in Rome, is a historical landmark. | which is in Rome | which |
| Tokyo, where the Olympics were held, is a bustling metropolis. | where the Olympics were held | where |
| My computer, which I use for work, is very reliable. | which I use for work | which |
| Jane Austen, whose novels are classics, is a beloved author. | whose novels are classics | whose |
| My neighbor, who is a retired teacher, is very knowledgeable. | who is a retired teacher | who |
| The Great Wall of China, which is a UNESCO World Heritage Site, is a remarkable structure. | which is a UNESCO World Heritage Site | which |
| Yesterday, when I visited the museum, I learned a lot. | when I visited the museum | when |
| My cat, which loves to sleep, is always relaxed. | which loves to sleep | which |
| The CEO, whose leadership is inspiring, has transformed the company. | whose leadership is inspiring | whose |
This table provides a helpful comparison of defining and non-defining clauses.
| Feature | Defining Relative Clause | Non-Defining Relative Clause |
|---|---|---|
| Purpose | Identifies the noun | Provides extra information |
| Essential Information | Yes | No |
| Commas | No commas | Set off by commas |
| Pronoun ‘that’ | Can be used for people and things | ‘That’ cannot be used; use ‘who’ or ‘which’ |
| Omission of Pronoun | Possible if the pronoun is the object | Not possible |
| Example | The book that I bought is interesting. | My book, which I bought yesterday, is interesting. |
Usage Rules
Understanding the rules governing the use of relative clauses is essential for accurate and effective writing.
Punctuation Rules
The most important punctuation rule is the use of commas with non-defining relative clauses. Remember that defining relative clauses never use commas.
- Non-defining relative clauses: Always use commas to separate the clause from the main sentence. One comma comes before the clause, and another comes after it, unless it ends the sentence.
- Defining relative clauses: Never use commas.
Choosing the Right Pronoun/Adverb
Selecting the correct relative pronoun or adverb depends on the noun being modified and the function of the pronoun/adverb within the relative clause. Refer to the section on relative pronouns and adverbs for a detailed explanation.
Formal vs. Informal Usage
In formal writing, it is generally preferred to use “whom” when it is the object of the relative clause. However, in informal speech and writing, “who” is often used instead.
Also, omitting the relative pronoun is more common in informal contexts.
Formal: “The man whom I spoke to was very helpful.”
Informal: “The man who I spoke to was very helpful.” OR “The man I spoke to was very helpful.”
Common Mistakes
Here are some common mistakes to avoid when using relative clauses:
- Incorrect punctuation: Using commas with defining relative clauses or not using commas with non-defining relative clauses.
- Wrong relative pronoun: Using “who” for things or “which” for people.
- Omitting the relative pronoun when it is the subject: This is incorrect. The relative pronoun must be present when it functions as the subject of the relative clause.
| Incorrect | Correct | Explanation |
|---|---|---|
| The book, that I read, was interesting. | The book that I read was interesting. | “That I read” is a defining relative clause and should not be set off by commas. |
| My sister who lives in London is a doctor. | My sister, who lives in London, is a doctor. | “Who lives in London” is a non-defining relative clause and should be set off by commas. |
| The car who I bought is red. | The car which I bought is red. | “Which” should be used for things, not “who.” |
| The person helped me was kind. | The person who helped me was kind. | The relative pronoun “who” cannot be omitted when it is the subject of the relative clause. |
| The woman, which I met, was nice. | The woman, whom I met, was nice. OR The woman, who I met, was nice. | “Who” or “Whom” should be used for people, not “which”. “Whom” is more formal. |
Practice Exercises
Test your understanding of relative clauses with these exercises.
Exercise 1: Identifying Relative Clauses
Identify the relative clause in each sentence and state whether it is defining or non-defining.
| Question | Your Answer |
|---|---|
| 1. The house that is on the corner is for sale. | |
| 2. My friend, who is a talented artist, is having an exhibition. | |
| 3. The book which I borrowed from the library is overdue. | |
| 4. My hometown, where I grew up, is a small village. | |
| 5. The student whose essay won the prize is very happy. | |
| 6. The movie that we watched last night was amazing. | |
| 7. My teacher, who is very knowledgeable, is always helpful. | |
| 8. The park where I walk my dog is very beautiful. | |
| 9. The song that she sang was very moving. | |
| 10. My cat, which is very lazy, sleeps all day. |
Answer Key:
| Question | Answer |
|---|---|
| 1. The house that is on the corner is for sale. | that is on the corner (defining) |
| 2. My friend, who is a talented artist, is having an exhibition. | who is a talented artist (non-defining) |
| 3. The book which I borrowed from the library is overdue. | which I borrowed from the library (defining) |
| 4. My hometown, where I grew up, is a small village. | where I grew up (non-defining) |
| 5. The student whose essay won the prize is very happy. | whose essay won the prize (defining) |
| 6. The movie that we watched last night was amazing. | that we watched last night (defining) |
| 7. My teacher, who is very knowledgeable, is always helpful. | who is very knowledgeable (non-defining) |
| 8. The park where I walk my dog is very beautiful. | where I walk my dog (defining) |
| 9. The song that she sang was very moving. | that she sang (defining) |
| 10. My cat, which is very lazy, sleeps all day. | which is very lazy (non-defining) |
Exercise 2: Punctuating Relative Clauses
Add commas where necessary in the following sentences.
| Question | Your Answer |
|---|---|
| 1. The car that I bought is very reliable. | |
| 2. My sister who lives in New York is a lawyer. | |
| 3. The book which is on the table is mine. | |
| 4. My house where I grew up is still standing. | |
| 5. The teacher whose class I enjoy is very funny. | |
| 6. The movie that won the Oscar was excellent. | |
| 7. My dog which is a Labrador loves to play fetch. | |
| 8. The restaurant where we had dinner is very expensive. | |
| 9. The dress that she wore was beautiful. | |
| 10. My friend who I met in college is visiting me. |
Answer Key:
| Question | Answer |
|---|---|
| 1. The car that I bought is very reliable. | The car that I bought is very reliable. (No commas) |
| 2. My sister who lives in New York is a lawyer. | My sister, who lives in New York, is a lawyer. |
| 3. The book which is on the table is mine. | The book which is on the table is mine. (No commas) |
| 4. My house where I grew up is still standing. | My house where I grew up is still standing. (No commas) |
| 5. The teacher whose class I enjoy is very funny. | The teacher whose class I enjoy is very funny. (No commas) |
| 6. The movie that won the Oscar was excellent. | The movie that won the Oscar was excellent. (No commas) |
| 7. My dog which is a Labrador loves to play fetch. | My dog, which is a Labrador, loves to play fetch. |
| 8. The restaurant where we had dinner is very expensive. | The restaurant where we had dinner is very expensive. (No commas) |
| 9. The dress that she wore was beautiful. | The dress that she wore was beautiful. (No commas) |
| 10. My friend who I met in college is visiting me. | My friend, who I met in college, is visiting me. |
Exercise 3: Combining Sentences
Combine the following pairs of sentences using a relative clause.
| Question | Your Answer |
|---|---|
| 1. I saw a movie. It was very interesting. | |
| 2. My neighbor is a doctor. He is very kind. | |
| 3. The book is on the table. I need it. | |
| 4. I visited Paris. It is a beautiful city. | |
| 5. The student is very smart. Her essay won the prize. | |
| 6. I bought a car. It is very fast. | |
| 7. My teacher is very helpful. She teaches English. | |
| 8. I went to a restaurant. It was very expensive. | |
| 9. She wore a dress. It was stunning. | |
| 10. I met a friend. He lives in London. |
Answer Key:
| Question | Answer |
|---|---|
| 1. I saw a movie. It was very interesting. | I saw a movie that was very interesting. |
| 2. My neighbor is a doctor. He is very kind. | My neighbor, who is a doctor, is very kind. |
| 3. The book is on the table. I need it. | The book that I need is on the table. |
| 4. I visited Paris. It is a beautiful city. | I visited Paris, which is a beautiful city. |
| 5. The student is very smart. Her essay won the prize. | The student whose essay won the prize is very smart. |
| 6. I bought a car. It is very fast. | I bought a car that is very fast. |
| 7. My teacher is very helpful. She teaches English. | My teacher, who teaches English, is very helpful. |
| 8. I went to a restaurant. It was very expensive. | I went to a restaurant that was very expensive. |
| 9. She wore a dress. It was stunning. | The dress that she wore was stunning. |
| 10. I met a friend. He lives in London. | I met a friend who lives in London. |
Advanced Topics
For advanced learners, here are some more complex aspects of relative clauses.
Reduced Relative Clauses
Reduced relative clauses are shortened relative clauses, often achieved by omitting the relative pronoun and auxiliary verb. This is common when the relative pronoun is followed by a form of “be.”
Example: “The book that is written by Hemingway is a classic.” can be reduced to “The book written by Hemingway is a classic.”
Another common reduction involves using a present participle (-ing form) when the relative clause describes an ongoing action.
Example: “The children who are playing in the park are having fun.” can be reduced to “The children playing in the park are having fun.”
Cleft Sentences with Relative Clauses
Cleft sentences are used to emphasize a particular part of a sentence. They often use a relative clause structure.
Example: Instead of saying “I bought the book,” you could emphasize that it was *the book* that you bought by saying “It was the book that I bought.”
Another common cleft structure uses “what”: “What I need is a vacation.” (This emphasizes “a vacation.”)
Cleft sentences provide an elegant way to shift the focus of a sentence and highlight specific information.
FAQ
Here are some frequently asked questions about relative clauses.
- What is the difference between “that,” “which,” and “who”?
Who is used for people. Which is used for things and animals. That can be used for both people and things in defining relative clauses, but it cannot be used in non-defining relative clauses. In non-defining relative clauses you must use ‘who’ or ‘which’.
- Can I always omit the relative pronoun when it is the object?
No, you can only omit the relative pronoun in defining relative clauses when it is the object of the verb. You cannot omit it if it is the subject of the relative clause, nor can you omit it in non-defining relative clauses.
- When do I use “whom” instead of “who”?
Use “whom” when the relative pronoun is the object of the verb or a preposition in the relative clause. However, “who” is often used instead of “whom” in informal English. If you are unsure, using “who” will generally be understood, especially in spoken English. In formal writing, “whom” is generally preferred.
- Are commas always required in non-defining relative clauses?
Yes, commas are always required to separate non-defining relative clauses from the main sentence. This is a strict grammatical rule.
- What happens if I use a comma with a defining relative clause?
Using a comma with a defining relative clause changes the meaning of the sentence. It suggests that the information in the relative clause is extra and not essential, which is incorrect for defining clauses. This can lead to confusion and misinterpretation.
- Can I use relative clauses with prepositional phrases?
Yes, you can. The preposition can either come before the relative pronoun (“to whom,” “with which”) or at the end of the relative clause (“who I spoke to,” “which I dealt with.”). Placing the preposition before the relative pronoun is more formal.
- What are the common mistakes when using relative clauses?
Common mistakes include incorrect punctuation (using commas with defining clauses or omitting them with non-defining clauses), using the wrong relative pronoun (e.g., “who” for things), and omitting the relative pronoun when it is the subject of the clause.
- How can I improve my understanding of relative clauses?
Practice identifying and using relative clauses in various contexts. Read widely and pay attention to how relative clauses are used in different types of writing. Do practice exercises and get feedback on your work. Focus on understanding the difference between defining and non-defining relative clauses and the correct punctuation for each.
- Can a relative clause modify another relative clause?
While unusual, a relative clause can technically modify a noun phrase that includes another relative clause. However, this can lead to very complex and often awkward sentence structures. It’s generally better to rephrase the sentence for clarity. For example, instead of “The book that I borrowed that was on the shelf is missing,” it’s clearer to say “The book that was on the shelf and that I borrowed is missing” or even simpler, “The book I borrowed from the shelf is missing.”
- Are there any regional variations in the use of relative clauses?
While the core rules of relative clauses remain consistent across English dialects, there can be subtle regional variations in pronoun preference and omission. For instance, the frequency of “that” versus “which” in defining relative clauses might vary slightly depending on the region. Similarly, the acceptability of ending a relative clause with a preposition (e.g., “the person I spoke to”) might be more relaxed in some dialects than others. However, these are minor variations and don’t fundamentally alter the grammatical rules.
- How do relative clauses translate into other languages?
The way relative clauses are expressed varies significantly across languages. Some languages use different grammatical structures altogether to convey the same information.
