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Relative clauses: non-defining relative clauses

Do you know how to use non-defining relative clauses?

Relative clauses - non-defining relative clauses

Relative clauses add extra information to a sentence by defining a noun. They are usually divided into two types – defining relative clauses and non-defining relative clauses.

Non-defining relative clauses

Look at this sentence.

  • My grandfather, who is 87, goes swimming every day.

‘who is 87’ is a non-defining relative clause. It adds extra information to the sentence. If we take the clause out of the sentence, the sentence still has the same meaning.

Look at some more examples.

  • My eldest son, whose work takes him all over the world, is in Hong Kong at the moment.
  • The film, which stars Tom Carter, is released on Friday.
  • The car, which can reach speeds of over 300km/ph, costs over $500,000.

In the first sentence, it is clear which son is being talked about and the relative clause provides extra information. In the second sentence, the speaker thinks you know which film you are talking about, and the information about Tom Carter is just something interesting. In the third sentence, the speaker thinks you already know which car is being discussed. The information about the speed is just for interest.

Defining or non-defining?

Remember that defining relative clauses are used to add important information. The sentence would have a different meaning without the defining relative clause.

  • I’m going to wear the skirt that I bought in London. 
  • The skirt, which is a lovely dark blue colour, only cost £10. 

The first sentence with a defining relative clause tells us which skirt. The second sentence, with a non-defining relative clause, doesn’t tell us which skirt – it gives us more information about the skirt. The context (which is missing here) makes it clear which skirt is being talked about.

Non-defining relative clauses can use most relative pronouns (which, whose etc,) but they CAN’T use ‘that’ and the relative pronoun can never be omitted.

  • The film, that stars Tom Carter, is released on Friday.

Non-defining relative clauses are more often used in written English than in spoken English. You can tell that a clause is non-defining because it is separated by commas at each end of the clause.



Language level

Intermediate: B1


Hello, dear teacher.
There aren't all the english grammars, and there is no grammars for advanced english grammars. We need more english grammar lessons because these grammars are not enough, so what should we do? But I appreciate the owner of this site because there we have enough chance to ask our questions. The owners of the site should have mentioned some sites for those, who want to pass TOEFL exam, as mentionded a link for IELTS learners.

Best regards!

Hello Ali Reza

We plan to create an Advanced grammar at some point, but I'm afraid it's going to be quite some time before we have it ready. In the meantime, the Grammar Reference has advanced points on many pages.

There are also other free resources on the internet, e.g. the Cambridge Dictionary, where you can find quite a lot of material.

Since the TOEFL isn't used by British institutions, we do not plan to create any resources for it. In addition to TakeIELTS, be sure to check out our FutureLearn courses.

All the best


The LearnEnglish Team

Is there any diffirence between meaning of these two Noun Clauses?
#1 I don't know if you are satisfied.
#2 I don't know wheter you are satisfied or not.

Hello Ali Reza

These two sentences have the same meaning.

All the best


The LearnEnglish Team

Dear Teachers,
Can non-defining relative clauses be reduced like defining clauses do (that is, 'be' + adjective phrase/prepositional phrase/participle can be reduced) ?
For example:
1) Her son, a dentist, lives in New York.
2) The Trumps. living in New York, arrived at my home yesterday
3) The building, going to be opened by the queen, cost over 5 million pounds
Thank you

Hello Kaisoo93

Non-defining relative clauses are not reduced like defining clauses are, so, for example, sentences 2 and 3 are not correct. 1 is correct, though it's not a case of a reduced non-defining clause -- instead it is an example of apposition.

All the best


The LearnEnglish Team

Hello Kirk,
Thank you for your reply.
I always come across sentences that reduce 'which means' to 'meaning', for example:
"There are lots of things that we have in English, meaning that (which means) we enjoy or experience them"
1) Is the sentence above considered non-defining relative clause?
2) Is this sentence correct? "I met Rebecca in town yesterday, which surprise me" If yes, can I reduce as "I met Rebecca in town yesterday, surprising me"? which I think is similar to the "which means" reduced to "meaning" case as above

Hello Kaisoo93

I'm afraid I don't understand that first sentence very well. Do you have another example? It'd be helpful to see it in context as well.

Yes, when 'which' refers to a whole clause rather than just a word (as in sentence 2), it is a non-defining relative clause. It is not correct to reduce sentence 2 in the way that you ask.

All the best


The LearnEnglish Team


Hello Kirk,
I found another sentence:
"Get together and implement the “English Only” rule while you hang out, meaning that everyone must only speak English for the next hour or two."
The "meaning that" in this sentence seems to be the reduced form of "which means". If this is the case, I wonder why the way I reduce "which surprises me" to "surprising me" in my second sentence is not correct.
Thank you

Dear teachers,
please tell me why in the second sentence, in the exercises, : "The building, which is going to be opened by the queen, cost over 5 million pounds" there is "cost" instead of "costs"?