“The car, that is red, is mine.”
Commas signal a non-essential clause; ‘that’ introduces an essential one. They don’t belong together.
Usage Entry 09 / 1011 60-second read
That vs. Which
Essential versus extra — a comma decides.
The comparisoni
“The car that is red is mine.”
No commas, because the clause tells us which car. Essential info.
More examplesii
01
The proposal which she drafted last week was approved.
The proposal that she drafted last week was approved.
No commas = essential clause — it identifies WHICH proposal. Use ‘that.’
02
The proposal that was drafted last week, and which ran to 40 pages, was approved.
The proposal, which was drafted last week and ran to 40 pages, was approved.
With commas = extra info — the clause is background. Use ‘which.’
The ruleiii
¶
THAT: essential. WHICH: extra.
If the clause is required to identify the noun, use THAT (no commas). If it’s just extra info, use WHICH (with commas).
Notesiv
Register
The THAT/WHICH distinction is enforced in American editing and most house styles. British English is more relaxed and often uses ‘which’ for essential clauses too.
Watch for
If the clause could be deleted without changing what the sentence refers to, it’s non-essential — set it off with commas and use WHICH.
Memory aidv
Remember it like this
Which can be whisked away (with the commas). That can’t.
In the wildvi
Real-world-style usage — how this looks in a sentence people would actually write.
- The book that won the Booker Prize was her second novel, which drew on her childhood.
- Any idea that survives the first draft is worth keeping — the rest, which usually lands in the bin, is noise.
Test yourselfvii
Which is right (American English)?