I have a cat which is purple.

I have a cat that is purple.

Which is correct?

Answer: Neither, I don't have a cat. My wife is allergic to them and her eyes pop out on stalks and turn red like large radishes. She forgets how to breathe and has to go to hospital. Besides, cats don't have owners, they have staff.

In fact, advice differs. Some say that both sentences are correct in British English. My view is that the second sentence is right. To differentiate them you need to know about relative restrictive clauses.

A restrictive clause is a clause containing important and essential information about the noun preceding it. In this case, use that. For everything else, use which. For example:

"F1 cars that use slick tyres go better in the wet". I warned you about English spellings back on page one, so don't moan. Here, the clause "that uses slick tyres" is essential to the meaning of the sentence. If you remove it you're left with "F1 cars go better in the wet", which is relatively meaningless. Better that what? In the first sentence the implication is that cars that use slick tyres go better than cars which don't. That's what the restrictive clause does.

"Which" would be used where no restrictive clause exists but where a non-restrictive clause might exist:

F1 cars, which are my favourite land vehicles, go very fast indeed.

Note two things: the non-restrictive clause (which are my favourite land vehicles) is surrounded by commas. Note also that if I remove that clause to leave, "F1 cars go very fast indeed", the overall meaning of the sentence is unchanged.

In this case always use "which". The commas are the clue.

This is as tough as this training will get, at least until we get to "who or whom", which coincidentally is next...

Tasks 0/2 completed
1. Have a short lie down before the next lesson.
2. Write a short review of the course on the opening page under Kyle's (just kidding).

Top Helpers in This Lesson

Join the Discussion
Write something…
Recent messages
christine2 Premium
I will leave now, because I am constantly picking up grammar and spelling mistakes in others, as well as on the news, in newspapers, in books, on the radio...
Not that mine is perfect, but I must have had VERY GOOD TEACHERS as I was painfully and deliberately acquiring English as my second language...I would never have had the guts to put anything up as training but I find it hilarious and can only commend you, Paul.I feel like I have found a soul mate griping about the same thing. I hope you have given a tutorial on my pet hate: the misuse of the words to lay and to lie. My patients always tell me they were laying down...their life, perhaps? And working in Ashton-under - Lyne near Manchester one of my patients proceeded to tell me: "I were just eating me tea, when..."
Coming from South Africa I never thought that i would need an interpreter for English, but there I did!
Paul Dean Premium
In Manchester (as elsewhere in England) people will happily admit to being "sat in front of the telly". I never occurs to them that by the same grammatical rules they should "get up and go for a walked". People seem particularly poor at tenses.

When ever I hear the word "sat" on telly I shout the word "sitting!" My wife just sighs.

I'll try to do "me" and "I" tomorrow, along with the correction to "me and him went out".
mrbill74 Premium
I'm forever correcting my girlfriend's comments, and it's reached the point where I simply brace myself after doing so--I KNOW she's going to smack me! These comments here remind me of a grammar course I enjoyed while still at AT&T. By the end of class, we came to three resolute conclusions:

1) It's not 'Lay Lady Lay', it's 'Lie Lady Lie';
2) It's not 'Lay Down, Sally', it's 'Lie Down, Sally'; and
3) It's not 'I Feel Good!', but 'I Feel Well'.

I may not have used the proper punctuation above, but this discussion is about grammar, right? :-)
speedking Premium
Hi Christine, good to hear from a fellow South African and great to meat up with you at WA ! I'm very new to all of this, but having a lot of fun doing it .Paul reminds me of one of my English teachers way back when in 'lekka" ol' SA.........keep up the good work Paul , there's always something new to learn.
RandyKR Premium
You should try to don' t lett it buggya so much.
JayandGlenda Premium Plus
Another one that bothers me is the misuse of the words I and me. Please clarify for those who obviously don't know any better.
mamalama Premium
As a home-school mom, I deal with grammar issues pretty regularly but I didn't have the guts to create grammar lessons for the WA community. This is a great service to many. Thanks a lot!
jespinola Premium
Interesting.. I will check my grammar :)
techhound Premium Plus
Hey Paul, great lesson. How about "Yore" being added to the last section? LOL.

Best Regards,
Paul Dean Premium
I'll do "yore" when I do "y'all". (No I won't).
techhound Premium Plus
LOL. Nice!