English Grammar: Punctuating (Commas) in Defining and Non-Defining Adjective Clauses

English Level: Upper-Intermediate

Language Focus: Comma usage in defining (restrictive) and non-defining (non-restrictive) adjective clauses

Worksheet Download: defining-adjective-clause-worksheet.docx (scroll down to study the exercises online)

Jump to: Explanation (below), Exercises

Note: An adjective clause and relative clause are the same. We will use the word adjective clause.

This is the third and final lesson on adjective clauses. We have studied the following:

  1. Lesson 1: Making adjective clauses with subject and object relative pronouns
  2. Lesson 2: Using the relative pronouns where, when, and which.

In this lesson, we will learn how to punctuate adjective clauses (with commas).

Introduction: Defining Adjective Clauses

Let's talk about children.

The child who is holding a bag is three years old.

The children in the photograph are outside. 

Can you understand the sentence? Yes. The subject of the sentence is 'The children' and there are two children in the picture. You can easily understand that 'The children' means to the children in the photograph.

In other words, we can say that the subject is defined; you have a clear understanding of who they are.

The child in the photograph is three years old.

Can you understand this sentence? No.

Which child is "The child"? It's not clear because there are two children. In order to understand the subject of the sentence, we need more information. We need to define the noun better.

The child who is carrying the bag is three years old.

Can you understand this sentence? Yes! The information in the adjective clause {who is carrying a bag} helps us define the subject. This information is necessary to understand which child is three years old. So we call this a 'defining adjective clause' (or restrictive adjective clause) because it gives us information that is necessary to define the noun. Without the adjective clause, the noun (the child) cannot be understood.

From this, we can understand the basic rules below.

Rule: When the adjective clause is necessary to define the noun, do not use commas.

Naturally, we use commas in the opposite case.

Rule: When the adjective clause is not necessary to define the noun, use commas.

Here's another example about the same photograph.

The girl is three years old. (The subject is defined. There is only one girl so it is clear who the girl is).

Now let's make an adjective clause with these two sentences.

The girl is three years old. She is carrying a bag.

If we replace the word 'she' with the relative pronoun 'who', and then move to the adjective clause behind the noun it modifies, we make this sentence:

The girl {who is carrying a bag} is three years old.

So, should we use commas or not? To answer the question, let's remove the adjective clause again.

The girl is three years old. <-- Can you understand this? Yes. Because there is only one girl; it is clear who she is. The subject is already defined.

In this case, we use commas to show that the adjective clause is just extra information (it is not necessary to understand the noun).

The girl, who is carrying a bag, is three years old.

That's the correct sentence.

Note: Extra Information is Not Part of Sentence Subjects

Let's talk about subjects.

The child who is carrying the bag is three years old.

The subject of this sentence is The child who is carrying a bag. This includes the adjective clause. This information cannot be removed because it is needed to define the noun child.

Now, what's the subject in this sentence?

The girl, who is carrying the bag, is three years old.

The subject is only The girl. The information in the adjective clause, separated by commas, is extra information. If you remove it, the sentence still has meaning (The girl is three years old).

Commas are one way that we add extra (non-essential) information to sentences. There are others.

  • The girl -- who is carrying a bag -- is three years old. = Here, the hyphen (--) is used to stress (emphasize) the information in the clause.
  • The girl, who is carrying a bag, is three years old. = Here the commas just add extra information
  • The girl (who is carrying a bag) is three years old. = Here the parentheses () are another way to add information that is not important.

All of these symbols -- the hyphen, comma, and parentheses, are used to add information in the same way.

Proper Nouns (Names of People/Places) Are Already Defined

The names of people and places, like John, New York, etc, are called proper nouns. These are specific names for something unique. There is only one of them, so they are already defined; they don't need any more information. Because of this, we always use commas after them, as in these examples:

  • Barack Obama, who had two daughters, was a president.
  • The Sun, which warms our planet, is hot.
  • He was born in Hawaii, which is a part of the United States.

All of these adjective clauses have commas and are non-defining adjective clauses.

Let's look at some examples and decide if we should add commas or not.

This website __ which you are using __ is free. 

The adjective clause is {which you are using}. Do we need this information to understand the noun, 'This website'? No. This website means THIS website, Englishcurrent.com. It's already clear to the reader. So, we would add commas because the adjective clause is not needed to define the noun.

This website, which you are using, is free.

Here's another example.

The woman __ who gave birth to you __ loves you.

If we removed the adjective clause {who gave birth to you}, could you understand the sentence? No. There are many women in the world. We need more information. What woman are you talking about? But, if we add the information {who gave birth to you}, can we understand which woman? Yes. We are talking about your mother. This information defines the noun, so we do not use commas.

The woman who/that gave birth to you loves you.

Important Note: The Relative Pronoun 'That' Is Never Used After Commas

In a non-defining adjective clause (an adjective clause with commas), the only relative pronouns you can use are who, whom, which, whose, where, and when. You cannot use 'that'. In English, we do not use that after a comma.

This webpage, {which/that has exercises below}, was written in 2017.

Last Point: Checking Meaning

Here is a classroom. Then look at these two sentences:

Kids in an ESL classroom maybe.

  1. The students who finished their homework left the classroom.
  2. The students, who finished their homework, left the classroom.

In sentence #1, how many students left the classroom? All or some? 

In sentence #2, how many students left? All or some? 

To answer these questions, remember that an adjective clause in commas is not necessary to understand the subject. So if we take it out, the meaning should be clear.

2. The students, who finished their homework, left the classroom. (This means that The students left the classroom (all of them).)

On the other hand, in sentence #1, if there are no commas, that means the adjective clause is necessary to understand the noun. This means the subject is The students who finished their homework... We know this group of students is different from 'The students' because there is no comma. In other words, 'who finished their homework' defines the noun. It makes it more specific. So there is a general 'The students' and a more specific 'The students who finished the homework'. There are two groups.

Do you understand? Let's see.


Exercise #1 - Understanding Sentence Meaning

Select the correct meaning of the sentence.

  1. The prisoners who were fighting will be punished. In other words,  of the prisoners will be punished.
  2. She took the bicycle which was on the side of the house. In other words, there was  bicycle.
  3. The manager yelled at the workers, who had arrived late. In other words,  of them arrived late.
  4. She really liked the painting that was near the door. In other words, there was  painting.
  5. The people who she remembered to email had brought their equipment. In other words,  of them brought equipment.
  6. She ate the pizza slice which didn't have any meat. In other words, there was  slice.


Exercise #2 - Punctuating Adjective Clauses

Change the second sentence into an adjective clause. Add commas if necessary.

1. Ron is on vacation. He is responsible for hiring.

Show Answer

2. Her husband works at IBM. You have met him.

Show Answer

3. Did you hear about the man? He swam across the Mediterranean Sea.

Show Answer

4. I'll always remember the time. I fell in love then.

Show Answer

5. Let's go to Bali. We can surf there.

Show Answer

5. The polar bear is the only animal. It hunts humans.

Show Answer

Exercise #3 - Add the Correct Relative Pronoun

  1. The students did not write the test failed.
  2. The singer, sung in Italian, sang five songs.
  3. Let's meet at the restaurant is next to the chemistry building.
  4. Alan teaches children ages range from 3 to 15 years old.
  5. I sometimes exercise with my father, is actually quite strong.
  6. The car crashed was a BMW.
  7. Her room was painted black, is not a cheerful color in my opinion.


Exercise #4 - Choose the Correct Adjective Clause

  1. There are many houses on my street. I live in the house . My house  is for sale.  I've decided that it's time .
  2. Yesterday, people came to look at the house. First, there was a woman named Cheryl . She said she was looking for a house . Later, a family came. The father said my neighbourhood looked like a place .
  3. I want to live somewhere . The city   is Los Angeles. My city doesn't have much nightlife .



I hope this lesson has been useful. If you find a mistake or have any questions, please leave a comment below.

-- Written by Matthew Barton (copyright) / Creator of Englishcurrent.com

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21 comments on “English Grammar: Punctuating (Commas) in Defining and Non-Defining Adjective Clauses

  1. Amir Amjad (Posted on 9-13-2017 at 01:53) Reply

    Outstanding sir ! It is very helpful…. Thanks a lot….

  2. blue blue sky (Posted on 12-12-2017 at 03:48) Reply

    Thank you for the lesson above.
    May i ask some questions?
    I have a headache on the bus coming here.

    Is the above sentence a correct one?
    I am confused of this sentence when i read this.
    Is the participle phrase coming here modify the word bus as the phrase follows the word bus , or it modifies the subject I or the whole clause, I have a headache on the bus.

    If modify the word bus, it’s like an adjective clause: I have a headache on the bus which comes here; this is how i analysed; is it correct?


    Putting a comma after the bus.
    I have a headache on the bus, coming here; to show the participle phrase modifying the whole clause, I have a headache.

    Or it can mean modifying the whole clause without putting a comma?

    Sorry for disturbing, thank you for your help :) ;)

    1. mb Post author (Posted on 3-3-2018 at 15:35) Reply

      ‘coming here’ can modify either the bus, or I, since both were coming. You can decide. If it modifies the word bus, then yes, it is like a reduced adjective clause. Instead of saying “that was coming here”, you delete the relative pronoun (that) and the be verb (was), and you are left with ‘coming here’.

      If you put a comma, it does seem to reflect the whole clause, not just the bus. I agree. It seems more natural to put the modifier at the beginning: ‘Coming here, I had a headache on the bus.’ With that order, it is clear that ‘coming here’ modifies ‘I’

  3. blue blue sky (Posted on 12-12-2017 at 03:51) Reply

    have a nice day :) ;)

  4. unknown (Posted on 12-18-2017 at 10:34) Reply

    nice exercises

  5. Anonymous (Posted on 3-3-2018 at 03:09) Reply

    Good lessons

  6. Andria (Posted on 12-2-2018 at 11:18) Reply

    I have been studying this in my university and i felt like my professor didn’t make much sense for me to understand, but when I found the website.. I’m just so happy and your teaching have made me understand a lot more ! thank you a lot for sharing this knowledge :)

  7. LiLi (Posted on 7-21-2019 at 00:39) Reply

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  8. Fan (Posted on 10-23-2019 at 10:24) Reply

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  9. Muhammad javaid (Posted on 12-22-2019 at 04:30) Reply

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  10. T_Y (Posted on 4-27-2020 at 10:44) Reply


  11. Anonymous (Posted on 6-7-2020 at 10:54) Reply

    This lesson is awesome. I don’t have words to define it.

  12. Sonia (Posted on 3-13-2021 at 07:17) Reply

    thanks , excellent page, very clear, could be more excercises is needed

  13. Abi (Posted on 6-7-2021 at 04:12) Reply

    Brilliant! Thank you.

  14. Anon (Posted on 8-24-2021 at 07:37) Reply


  15. Katherine (Posted on 3-8-2022 at 11:21) Reply

    Im realizing how bad my writtings are. :( Thanks for this exercise!

  16. Farnaz Malek (Posted on 6-4-2022 at 21:44) Reply

    Thank for your brief and helpfule teaching method which elaborate and support every topic with awsome exercises and tests with a very clear explanation ! You’re the best

  17. Victoria P (Posted on 2-16-2023 at 08:47) Reply

    Sentence number one some of the students left the classroom and sentence number two all of the students left the classroom.

  18. Pavlo Horkun (Posted on 5-11-2023 at 17:26) Reply

    Nice lesson, easy for understanding with clear examples

  19. Iryna (Posted on 5-11-2023 at 17:57) Reply

    It’s very good lesson due to clear explanations and many examples. Thank you.

  20. xena (Posted on 6-11-2023 at 11:48) Reply

    Very nice lesson. i really enjoyed it.

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