Non-Defining Clauses: Adding Extra Info (with commas)
Grammar Rule in 30 Seconds
Non-defining clauses add extra, non-essential information about a noun using commas and relative pronouns like 'who' or 'which'.
- Always use commas to separate the extra info from the main sentence: 'My brother, who lives in Paris, is a chef.'
- Never use the word 'that' in these clauses; stick to 'who', 'which', 'whose', or 'where'.
- The sentence must still make perfect sense if you remove the entire clause between the commas.
Overview
We add extra facts about a person or thing. We already know who they are. These facts are just extra details.
Use commas for the extra words. Commas show the words are extra. The sentence is perfect without them.
This helps you speak and write well. It is good for school and work. It makes your English better.
Read this: 'My boss, who likes AI, said yes.' 'Who likes AI' is extra. 'My boss said yes' is clear.
How This Grammar Works
Who: Used for people as the subject or object of the relative clause's verb.
Ms. Jenkins, who leads the marketing team, presented the quarterly report.Whom: Used for people as the object of the relative clause's verb or a preposition. It is considerably more formal and less common in everyday spoken English thanwho.
Whose: Indicates possession for both people and things.
Which: Used for things, animals, or abstract concepts.
The new office building, which features sustainable architecture, will open next month.Where: Used for places.
Paris, where I hope to study next year, is a vibrant cultural hub.When: Used for times.
My birthday, when we usually have a family gathering, falls on a Tuesday this year.Formation Pattern
My mentor, who previously worked at Google, provided invaluable career advice.
,
,
We visited the historic library, which houses over a million rare books.
,
Our professor, whom the students respect, lectured for two hours. |
The ancient city, whose ruins are well-preserved, attracts tourists. |
The café, where we often meet, serves excellent coffee. |
Next Tuesday, when the new policy takes effect, will be busy. |
The committee, to whom the proposal was submitted, will vote next week.
The research paper, about which there was much debate, explored novel theories.
The student, who I often collaborate with, secured a scholarship. (Informal for with whom I often collaborate)
When To Use It
- 1Adding Background or Context to a Unique Entity: When referring to a person, place, or thing that is already singular or unambiguously identified (e.g., by a proper noun, a demonstrative, or a unique descriptor), a non-defining clause can provide supplementary facts without changing the core identification. This is particularly useful in biographies, news reports, or academic writing.
Dr. Evelyn Reed, who holds a PhD in computational linguistics, heads the research department.(There is only oneDr. Evelyn Reedin this context, sowho holds a PhD in computational linguisticsis extra detail.)The Amazon River, which is the largest river by discharge volume, flows through South America.
- 1Providing General Information or Commentary: You can use these clauses to offer a general observation, an opinion, or extra evaluative information about a preceding statement or concept. In this use, the
whichclause can refer to the entire preceding clause or sentence, not just a single noun.
The team decided to work overtime, which was an unexpected but necessary decision.(whichrefers to the entire action ofthe team decided to work overtime.)She successfully defended her thesis, which made her parents immensely proud.
- 1Enhancing Cohesion and Flow: Instead of breaking information into multiple, short sentences, non-defining clauses allow for the elegant integration of related ideas. This creates a smoother reading experience and contributes to a more mature writing style, particularly important in formal essays, reports, and presentations. It demonstrates an ability to connect ideas logically within a single sentence structure.
- Instead of:
The conference will be held in Berlin. Berlin is known for its vibrant startup scene. - Use:
The conference will be held in Berlin, which is known for its vibrant startup scene.
- 1Giving Specific Details about Times or Places:
Whenandwherecan introduce non-defining clauses to provide additional context about a specific temporal or spatial reference.
My graduation day, when my entire family flew in, was a truly memorable occasion.The old marketplace, where local artisans display their crafts, is a popular tourist spot.
- 1Formal Communication: Non-defining clauses are frequently encountered in formal writing (e.g., academic papers, legal documents, official reports) where precision and the ability to convey complex relationships between ideas are paramount. They allow for dense information packaging without sacrificing clarity.
The newly enacted legislation, which aims to reduce carbon emissions, faces strong opposition from industrial lobbies.
Common Mistakes
- 1Omitting the Commas: This is arguably the most prevalent and impactful error. Without commas, a non-defining clause defaults to being interpreted as a defining clause, which fundamentally alters the sentence's meaning. This occurs because the punctuation (or lack thereof) dictates the clause's grammatical function.
- Incorrect:
My sister who works in London is visiting next week.(Implies you have multiple sisters, and only the one in London is visiting. The clause defines which sister.) - Correct:
My sister, who works in London, is visiting next week.(Implies you have one sister, and she works in London. The clause provides extra information about your already identified sister.)
- 1Using
thatfor Non-Defining Clauses: As previously stated,thatis exclusively reserved for defining relative clauses. Its use in a non-defining context is grammatically incorrect.
- Incorrect:
The new headquarters, that opened last month, features a rooftop garden. - Correct:
The new headquarters, which opened last month, features a rooftop garden.
- 1Incorrect Relative Pronoun Choice (
whovs.which): Learners sometimes confusewho(for people) andwhich(for things, animals, concepts).
- Incorrect:
The scientist, which discovered the new element, received a Nobel Prize. - Correct:
The scientist, who discovered the new element, received a Nobel Prize. - Incorrect:
The experiment, who yielded surprising results, was replicated globally. - Correct:
The experiment, which yielded surprising results, was replicated globally.
- 1Misplacement of the Clause: A non-defining clause must directly follow the noun phrase it modifies. Placing it elsewhere can lead to ambiguity or create grammatically awkward sentences.
- Awkward/Incorrect:
The report was due on Friday, which contained critical data.(SuggestsFridaycontained data.) - Correct:
The report, which contained critical data, was due on Friday. - Correct:
The report was due on Friday, and it contained critical data.(Alternative without a relative clause ifFridayis the main focus.)
- 1Overuse or Redundancy: While valuable, overusing non-defining clauses, or using them to state obvious information, can make writing cumbersome and less impactful.
- Less impactful:
The sun, which is a star, provides light and warmth.(The fact that the sun is a star is generally known and not highly essential extra info for many contexts). - Better (if the fact isn't crucial for the audience):
The sun provides light and warmth.
Real Conversations
Non-defining relative clauses are not confined to formal academic texts; they are integral to natural, nuanced communication across a spectrum of modern contexts. Their presence allows for a more fluid exchange of information and adds depth to both casual and professional interactions.
1. Professional Correspondence (Emails, Reports): In the workplace, these clauses are invaluable for providing context, clarifying roles, or adding background to decisions without needing separate sentences.
- Email: Regarding the upcoming client meeting, Mr. Henderson, who manages the international accounts, will present the new proposal.
- Report: The latest market analysis, which indicates a shift in consumer preferences, suggests a revision of our product strategy.
2. Casual Conversations and Social Media: While often perceived as formal, non-defining clauses frequently appear in spoken English and online interactions to inject quick, additional details.
- Texting: Just saw Sarah, who just got back from her trip, at the coffee shop. She looked great!
- Social Media Post: Had an amazing dinner at 'The Bistro,' which has the best pasta in town! #foodie
- Online Review: The new concert venue, where parking is surprisingly ample, offered a fantastic acoustic experience.
3. News and Journalism: News articles frequently use non-defining clauses to provide immediate background information about individuals, organizations, or events, allowing for concise reporting.
- The Prime Minister, who is currently attending the G7 summit, addressed concerns about economic stability.
- The historic treaty, which was signed in 1995, continues to shape international relations.
4. Academic Discussions and Presentations: In educational settings, these clauses are crucial for building arguments, defining terms, and attributing sources clearly and concisely.
- The theory of relativity, which was proposed by Albert Einstein, revolutionized physics.
- Our research methodology, which relies heavily on qualitative data analysis, necessitated extensive fieldwork.
These examples illustrate that non-defining relative clauses are not merely a grammatical exercise but a practical tool for effective communication. They allow you to embed extra information gracefully, making your English sound more polished, precise, and native-like. Their usage reflects an advanced capability to synthesize and present information efficiently, moving beyond simple sentence structures to articulate complex ideas with greater fluency.
Quick FAQ
The core difference lies in the essentiality of the information. A defining clause provides information necessary to identify or define the noun it modifies; without it, the noun is ambiguous. A non-defining clause provides additional, non-essential information about an already identified noun. Its removal does not alter the fundamental meaning or identification of the noun.
Commas are the grammatical markers that signal the clause is parenthetical and contains non-essential information. They instruct the reader or listener to treat the enclosed information as supplementary, indicating it could be omitted without loss of the main idea. Their absence changes the clause's grammatical function to defining, which leads to different meaning and can introduce ambiguity.
No, that is strictly reserved for defining relative clauses. Using that in a non-defining clause is a grammatical error. Always use who, whom, whose, which, where, or when for non-defining clauses.
If you omit the commas, the clause will be interpreted as a defining clause. This can drastically change the meaning of your sentence, sometimes making it illogical or conveying unintended information. For instance, My brother who lives in London is a doctor implies you have multiple brothers and specifies the one in London, whereas My brother, who lives in London, is a doctor indicates you have one brother, and incidentally, he lives in London.
Whom is used when the relative pronoun is the object of the verb or a preposition within the relative clause. It is considered more formal than who. For example, The director, whom the entire cast admired, gave a farewell speech (object of admired). Or The colleague, with whom I shared the project, transferred departments (object of preposition with). In informal contexts, who is often used even as an object, but whom is strictly correct in formal English.
Yes, a which non-defining clause can sometimes refer to an entire preceding statement or action, not just a single noun. This usage adds commentary or consequence to the preceding idea. For example, He missed the train, which meant he would be late for the meeting. Here, which refers to the entire act of missing the train.
While frequently appearing mid-sentence, non-defining clauses can also appear at the end, provided the noun phrase they modify is the final element of the main clause. In such cases, the clause is preceded by a single comma and concludes the sentence. For example, I finally visited the Grand Canyon, which is even more spectacular in person.
Relative Pronoun Selection
| Target | Pronoun | Example Clause |
|---|---|---|
|
People
|
who
|
, who lives next door,
|
|
Things/Animals
|
which
|
, which cost $50,
|
|
Possession
|
whose
|
, whose car was stolen,
|
|
Places
|
where
|
, where we met,
|
|
Time
|
when
|
, when the sun sets,
|
|
Whole Sentences
|
which
|
, which is why I'm late.
|
Meanings
A non-defining relative clause provides additional information about a person, thing, or place that is already clearly identified. It is not essential for the sentence to be understood.
Adding info about people
Using 'who' to provide biographical or situational details about a specific person.
“Mr. Smith, who is 70 years old, still goes jogging every morning.”
“My sister, who you met yesterday, is moving to Canada.”
Adding info about things
Using 'which' to describe an object or concept that has already been named.
“The Taj Mahal, which was built in the 17th century, is a UNESCO World Heritage site.”
“My new phone, which cost a fortune, is already broken.”
Possession with 'whose'
Adding extra info about who something belongs to.
“The neighbor, whose dog barks all night, is actually very nice.”
“The company, whose profits have doubled, is hiring new staff.”
Adding info about places
Using 'where' to give extra context about a location.
“Paris, where I spent my honeymoon, is beautiful in the spring.”
“The local park, where we used to play football, has been closed.”
Commenting on a whole sentence
Using 'which' after a comma to comment on the entire preceding clause.
“He arrived late, which was very rude.”
“She passed the exam, which surprised everyone.”
Reference Table
| Type | Structure | Example |
|---|---|---|
|
Affirmative (Subject)
|
Noun, who/which + verb, ...
|
John, who is my cousin, is here.
|
|
Affirmative (Object)
|
Noun, who/which + subject + verb, ...
|
The car, which I bought, is blue.
|
|
Negative
|
Noun, who/which + negative verb, ...
|
The cake, which wasn't sweet, was bad.
|
|
Possessive
|
Noun, whose + noun + verb, ...
|
The man, whose dog died, is sad.
|
|
Place
|
Noun, where + subject + verb, ...
|
London, where I live, is cold.
|
|
Sentence Comment
|
Clause, which + verb
|
He lied, which was disappointing.
|
|
Final Position
|
Main Clause, who/which + verb.
|
I saw Mary, who was very happy.
|
Formality Spectrum
My brother, who resides in London, is a medical practitioner. (Family description)
My brother, who lives in London, is a doctor. (Family description)
My brother, who's living in London now, is a doctor. (Family description)
My bro, who's up in London, is a doc. (Family description)
The Anatomy of a Non-Defining Clause
Punctuation
- Comma 1 Before the clause
- Comma 2 After the clause
Relative Pronouns
- Who People
- Which Things
- Whose Possession
Function
- Extra Info Not essential
- Specific Noun Already identified
Defining vs. Non-Defining
Should I use commas?
Is the noun a specific name or already identified?
If you remove the info, is the sentence still clear?
Examples by Level
My dad, who is a teacher, is nice.
London, which is big, is in England.
My car, which is red, is fast.
Sarah, who is my friend, is here.
My house, which has three bedrooms, is old.
The teacher, who is very kind, helped me.
Paris, where the Eiffel Tower is, is beautiful.
My brother, whose name is Tom, is a doctor.
The new shopping mall, which opened last week, is huge.
My boss, who travels a lot, is in New York now.
The movie, which we saw yesterday, was quite boring.
Italy, where my parents were born, is a sunny country.
The company, which was founded in 1920, is going bankrupt.
He forgot my birthday, which made me very angry.
The scientist, whose research is famous, won a prize.
The hotel, where we stayed for two weeks, was excellent.
The proposal, which the board rejected yesterday, was very detailed.
The city, the history of which is fascinating, attracts many tourists.
The witness, who had been silent until then, finally spoke.
The project, which I have been working on for months, is finally finished.
The Prime Minister, whose popularity has waned recently, faces a challenge.
The cathedral, the construction of which took 200 years, is a masterpiece.
He was unable to attend, which, given the circumstances, was understandable.
The theory, which has been widely criticized, remains influential.
Easily Confused
Learners don't know when to use commas and when not to.
Learners want to use 'that' in all relative clauses.
Common Mistakes
My brother that is tall is here.
My brother, who is tall, is here.
London which is big is in England.
London, which is big, is in England.
My car, that I bought last year, is broken.
My car, which I bought last year, is broken.
The city where I was born in is beautiful.
The city, where I was born, is beautiful.
Sentence Patterns
[Proper Name], who ___, is ___.
[Specific Object], which ___, was ___.
[Clause], which ___.
Real World Usage
The President, who is 78, arrived today.
My cat, which is literally a demon, just broke my vase.
My last project, which I led for six months, was a success.
The hotel, where we stayed last summer, has closed down.
I saw Sarah, who says hi btw.
This theory, which was developed in 1920, is still used.
The 'That' Rule
The Deletion Test
Proper Names
Speaking Pauses
Smart Tips
Always use commas. Since the name already identifies them, any extra info is by definition 'non-defining'.
Use ', which' at the end of your sentence to add a comment.
Make sure the place is a setting. If you are describing the place as an object, use 'which'.
Combine them! Use a non-defining clause to turn two boring sentences into one interesting one.
Pronunciation
The Comma Pause
In speech, there is a slight pause and a drop in pitch at each comma.
Parenthetical Dip
The car, ↘ which was red, ↗ is mine.
The lower pitch indicates the information is secondary.
Memorize It
Mnemonic
Commas are like handles on a suitcase: they hold the extra stuff you're carrying.
Visual Association
Imagine a 'comma sandwich'. The two commas are the bread, and the extra information is the delicious filling. Without the bread, the filling falls out and makes a mess!
Rhyme
If the info is just a plus, use a comma and don't make a fuss.
Story
A detective is describing a suspect. 'The man is tall.' (Boring). 'The man, who was wearing a red hat, is tall.' The red hat is the extra clue that helps the story but isn't the main point.
Word Web
Challenge
Look at three objects in your room. Write one sentence for each using a non-defining clause (e.g., 'My laptop, which I bought last year, is on the desk.').
Cultural Notes
British speakers are often very strict about using 'which' for non-defining clauses and 'that' for defining ones.
News outlets like the BBC or NYT use these clauses to provide titles and ages efficiently.
Non-defining clauses are used to cite sources or provide definitions without stopping the flow.
Relative clauses in English evolved from demonstrative pronouns in Old English.
Conversation Starters
Tell me about your best friend, who I haven't met yet.
What is your favorite city, which you've visited recently?
Tell me about your first car, which you probably don't have anymore.
Journal Prompts
Common Mistakes
Test Yourself
Which sentence is punctuated correctly?
Paris, ___ is the capital of France, is beautiful.
Find and fix the mistake:
My car, that I bought last week, is already broken.
Mr. Jones is our neighbor. He is 80 years old.
You can use 'that' in a non-defining relative clause.
The book, which I finished yesterday, was great.
Match each item on the left with its pair on the right:
my / which / is / old / car / , / red / , / is
Score: /8
Practice Exercises
8 exercisesWhich sentence is punctuated correctly?
Paris, ___ is the capital of France, is beautiful.
Find and fix the mistake:
My car, that I bought last week, is already broken.
Mr. Jones is our neighbor. He is 80 years old.
You can use 'that' in a non-defining relative clause.
The book, which I finished yesterday, was great.
Match the following:
my / which / is / old / car / , / red / , / is
Score: /8
Practice Bank
12 exercisesMy phone ___ I bought last year, is already acting up.
My boss, that is usually very strict, was surprisingly lenient today.
Choose the correct sentence:
Translate into English: 'Mi hermana, que vive en Madrid, viene a visitarme.'
Arrange these words into a sentence:
Match the subjects with the correct non-defining clause:
The concert, ___ tickets sold out in minutes, was spectacular.
The movie, I watched last night, was incredibly boring.
Choose the correct sentence:
Translate into English: 'El lunes, cuando tengo mi examen final, estaré muy estresado.'
Arrange these words into a sentence:
Match the main clause beginnings with appropriate non-defining clause endings:
Score: /12
FAQ (8)
No, never. In English, 'that' is strictly for defining clauses. If you have commas, you must use 'who' or 'which'.
It creates a 'run-on' feeling and can confuse the reader about where the main verb of the sentence is.
Yes, in very formal writing, 'whom' is used if the person is the object of the clause: 'My boss, whom I respect, is leaving.'
Yes! This is called a sentential relative clause. Example: 'He was late, which was annoying.'
You only need the first comma. Example: 'I live in London, which is a big city.'
Try the 'Deletion Test'. If you remove it and the sentence still identifies the noun clearly, it's extra (non-defining).
Yes, for places. 'My school, where I studied for 5 years, is closing.'
It is very common in both, but you will see much longer and more complex ones in formal writing.
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
Oraciones de relativo explicativas
Spanish uses 'que' for both; English requires 'which/who' and forbids 'that'.
Relativsätze
German always uses commas; English only uses them for non-defining clauses.
Propositions subordonnées relatives
French 'que' is used for objects, while English uses 'which' or 'who(m)'.
連体修飾節 (Rentai shuushikusetsu)
Japanese has no relative pronouns and the clause precedes the noun.
الصلة (Al-Sila)
Arabic relative pronouns change based on gender and number, and the definite/indefinite distinction is crucial.
的 (de) structure
Chinese puts all descriptions before the noun using 'de'.
Learning Path
Prerequisites
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