Question 1

What is a non-defining relative clause?

Accepted Answer

A non-defining relative clause adds extra information about a noun that is already identified or unique. It does not tell us which person or thing we mean — the noun is already clear. For example: "My mother, who is a teacher, loves reading" — I only have one mother, so "who is a teacher" is not needed to identify her. These clauses are always placed between commas and can be removed without changing the core meaning of the sentence. They are common with proper nouns (names of people, places, and things) because proper nouns are already unique and do not need further identification.

Question 2

How do I punctuate non-defining relative clauses correctly?

Accepted Answer

Always use commas to separate a non-defining clause from the rest of the sentence. If the clause is in the middle, use two commas — one before and one after: "My brother, who lives in Wales, is visiting." If the clause is at the end, use one comma before it: "I called Tom, who was happy to hear from me." Never use a comma with defining clauses — "The man, who called, is my brother" changes the meaning to non-defining. In exams, incorrect punctuation often costs marks because it changes the type of clause and therefore the meaning of the sentence.

Question 3

Can I remove a non-defining relative clause from a sentence?

Accepted Answer

Yes, that is one of the key features of non-defining clauses. Because they add extra, non-essential information, removing them leaves a complete sentence with the same basic meaning. "The Thames, which runs through London, is the longest river in England" — remove the clause and you get "The Thames is the longest river in England," which is still perfectly clear and grammatically complete. If removing the clause makes the sentence unclear or changes who or what you are talking about, it is actually a defining clause and should not have commas.

Non-Defining Relative Clauses Exercises

Quick Rule

All 20 questions

Continue Practising

Relative Clauses Error Correction

Who vs Which

Defining vs Non-Defining

-ed vs -ing Adjectives

Conditionals

Present Perfect