Defining and Non-Defining Relative Clauses helps you communicate about identification versus extra description. Start with the meaning, notice the pattern, and then use it in complete sentences.
By the end of this lesson, you can
- I can distinguish essential identifying information from additional non-essential information.
- Recognise and build the form: defining clause without commas; non-defining clause with commas and no 'that'.
- Use the pattern accurately in a meaningful sentence.
Meaning and use
Use Defining and Non-Defining Relative Clauses for identification versus extra description. Always read the whole situation before choosing the form: grammar expresses a meaning, not only a pattern.
My brother, who lives in Seoul, is visiting next week.
A non-defining clause about a person uses 'who' and is separated by commas.
Employees who arrive late must report to reception.
This defining clause identifies which employees; no commas are needed.
The report, which was published yesterday, contains new data.
A non-defining clause about a thing uses 'which', not 'that'.
defining clause without commas; non-defining clause with commas and no 'that'Keep this pattern visible while you study the examples. Then cover it and rebuild one example from memory.
Key rules to notice
These rules explain why the form is correct. Focus on the subject, auxiliary, verb form, word order and time or meaning clues.
- A non-defining clause about a person uses 'who' and is separated by commas.
- This defining clause identifies which employees; no commas are needed.
- A non-defining clause about a thing uses 'which', not 'that'.
- A defining clause can use 'that' to identify specific things.
- Use 'where' in a non-defining clause referring to a place.
Common mistakes
Not:My brother, that lives in Seoul, is visiting next week.
Use:My brother, who lives in Seoul, is visiting next week.
A non-defining clause about a person uses 'who' and is separated by commas.
Not:Employees which arrive late must report to reception.
Use:Employees who arrive late must report to reception.
This defining clause identifies which employees; no commas are needed.
Not:The report, that was published yesterday, contains new data.
Use:The report, which was published yesterday, contains new data.
A non-defining clause about a thing uses 'which', not 'that'.
Check before you practise
Complete each sentence mentally, then reveal the answer.
The files ____ you requested are attached.
that
A defining clause can use 'that' to identify specific things.
Paris, ____ we spent our honeymoon, is beautiful in spring.
where
Use 'where' in a non-defining clause referring to a place.
Students ____ essays are selected will receive a prize.
whose
'Whose' identifies students by possession of the selected essays.