use of comma for 'which' and 'that'

This topic has expert replies
Junior | Next Rank: 30 Posts
Posts: 24
Joined: Sun May 11, 2008 10:56 pm

use of comma for 'which' and 'that'

by raptor84 » Mon Feb 09, 2009 3:46 am
hey guyz..

is it true that a comma should always precede the pronoun which??

For example,

My car, which is red in color, is ten years old
My car which is red in color is ten years old

Are both the sentences above correct??

If its a rule that a comma should always precede the pronoun which, then can i safely assume that all sentences that use the pronoun which without the comma before it are incorrect even if the pronoun refers to the proper noun??

Legendary Member
Posts: 940
Joined: Tue Aug 26, 2008 3:22 am
Thanked: 55 times
Followed by:1 members

Re: use of comma for 'which' and 'that'

by iamcste » Mon Feb 09, 2009 3:52 am
raptor84 wrote:hey guyz..

is it true that a comma should always precede the pronoun which??

For example,

My car, which is red in color, is ten years old
My car which is red in color is ten years old

Are both the sentences above correct??

If its a rule that a comma should always precede the pronoun which, then can i safely assume that all sentences that use the pronoun which without the comma before it are incorrect even if the pronoun refers to the proper noun??
Yes ! Non essential modifers such as "which" use comma to differentiate from essential modifiers such as "that"

That said, in GMATLand, first one is correct. For the second one "That" must be used

But do not follow this rule blindly...Also look for potential errors in such sentences. If all the other options have potential errors and I have a sentence without comma and no other potential error, I would choose it.

User avatar
Master | Next Rank: 500 Posts
Posts: 226
Joined: Tue Jan 13, 2009 1:27 pm
Thanked: 23 times
Followed by:1 members
raptor84 wrote:hey guyz..

is it true that a comma should always precede the pronoun which??

For example,

My car, which is red in color, is ten years old
My car which is red in color is ten years old

Are both the sentences above correct??

If its a rule that a comma should always precede the pronoun which, then can i safely assume that all sentences that use the pronoun which without the comma before it are incorrect even if the pronoun refers to the proper noun??
As noted above, you use THAT for ESSENTIAL modifiers. You use WHICH for NON-ESSENTIAL modifers. Also, WHICH will almost always be preceded by a comma because it starts a NON-ESSENTIAL modifier.

The above sentence is basically stating that "My car is ten years old". The fact that it is red in color is not essential to the statement. Therefore, you would use WHICH, preceded by a comma.

If the statement were:

The tallest mountain on Earth is Mount Everest THAT is on the border between Nepal and Tibet.

This would be wrong. Everything before "THAT" is the important part of the sentence. Everything after that is NON-ESSENTIAL.

Thus, this sentence should be written as

The tallest mountain on Earth is Mount Everest, which is on the border between Nepal and Tibet.

Remember: ,WHICH = NON-ESSENTIAL MODIFIER
THAT = ESSENTIAL MODIFER

User avatar
Master | Next Rank: 500 Posts
Posts: 103
Joined: Wed Feb 23, 2011 10:38 am
Location: India
Thanked: 7 times
Followed by:3 members
GMAT Score:730

by itheenigma » Wed Sep 14, 2011 10:12 pm
This cannot be considered as a rule.
I have seen instances where a 'which' modifier is treated as an essential modifier.

That said, I can probably agree on the fact that a 'which' modifier preceded by a comma will be a non essential modifier. I guess I can even generalize that all modifiers preceded by a comma are non essential; else not. 'which'/'that' don't serve as the perfect yardsticks for making that decision.

Master | Next Rank: 500 Posts
Posts: 416
Joined: Thu Jul 28, 2011 12:48 am
Thanked: 28 times
Followed by:6 members

by gunjan1208 » Thu Sep 15, 2011 1:40 am
Hi itheenigma,

You are right, and, I think, that's what others meant too.

Non essential modifiers are the one wherewe use, bofore "which".....

This car,which is mine, is red. (We i get to know concrete information with "this", other information "which is mine" is non essential and this sentence can stand even without this.

However,

The car that/which is red is mine (That is preferable: Choose which with essential modifier when GMAT foreces you to): If we remove that/which is red, the sentence is really awkward...

Agree?

Thank you!!

Newbie | Next Rank: 10 Posts
Posts: 9
Joined: Sun May 15, 2011 6:10 pm

by vikram.sumer » Tue May 01, 2012 6:10 am
It is misleading and oversimplistic to say that "which" must always be preceded by a comma. The rule is that a nonrestrictive clause should be set off with commas, but a nonrestrictive clause does not always begin with "which," and the presence of "which" does not always signal a nonrestrictive clause.

First of all, if the relative pronoun is the object of a preposition, whether the clause is restrictive or nonrestrictive, you cannot use "that"; you must use "which." Here are a couple of correct sentences from the Official Guide that use "which" after a preposition in a restrictive clause:

El Nino, the periodic abnormal warming of the sea surface off Peru, is a phenomenon in which changes in the ocean and atmosphere combine to allow the warm water that has accumulated in the western Pacific to flow back to the east.

As U.S. nuclear attack submarines prowl their familiar haunts deep within the oceans of the world these days, they increasingly are engaged in missions far different from the tasks for which they were built and for which their crews were trained over the last forty years.

Second, in contemporary English usage, "which" is very often used where traditionalists would prefer "that." According to The Little, Brown Handbook:

"Which" can introduce both restrictive and nonrestrictive clauses, but many writers reserve "which" only for nonrestrictive clauses.

Still, what concerns us here is what GMAT writers think, and if you look at the explanation to OG11 SC7 you will see that choice A is wrong in part because "Which is incorrectly used for a clause that defines," and that choice C is wrong in part because "Which incorrectly introduces a restrictive clause." It is worth noting, however, that both of these wrong choices have other problems; misuse of "which" is not the only reason to eliminate them.

The fact is that a study of edited prose has shown that about 75 percent of the instances of "which" introduce restrictive clauses and only about 25 percent introduce nonrestrictive clauses.


OP- Bob@urch forum