ashijain wrote:
Hi GMAT Ninja,
Please explain the difference in usage of WHICH and THAT. I am really struggling with it.
Hi, I know that I am not GMAT Ninja, but I happened to be studying about this a few days ago and thought my notes could help you!
To understand the usage of Which and That, you first need to understand restrictive clauses and non-restrictive clauses.
Restrictive Clauses: 1. CANNOT be omitted from the sentence without changing the meaning.
2. are always vital modifiers.
3. Not separated from the sentence.
4. Who, which and THAT can be used.
Non-Restrictive Clauses:1. Can be omitted from the sentence without changing the meaning.
2. Are always non-vital modifiers.
3. Separated from the sentence with the comma.
4. Who, which, and who can be used. But THAT CANNOT be used.
For example,
The guy who is giving the speech on the stage is my dad. This is a
restrictive clause because
1. "Who..." is not separated from the sentence.
2. If "who.." were removed, the meaning of the sentence would be affected. (The guy
who is giving the speech on the stage is my dad is still correct grammatically, but the meaning is different)
Jason, who's traveling in Japan now, is going to college next month.This is a
non-restrictive clause because
1. The "who..." modifier is separated from the sentence by commas.
2. If "who..." were removed, the meaning of the sentence stays the same. (Jason
, who's traveling in Japan now,is going to college next month.)
Basically, "Which" could be removed without changing the meaning of the sentence and be separated by commas. "That", if removed, will change the meaning of the sentence, and "THAT", when used as a modifier, should not be separated by commas.*I mentioned vital & non-vital modifier is to establish that vital noun modifier can come between a noun and non-vital modifier.
This is why sometimes the antecedent of the relative pronoun clause isn’t the immediate noun or noun phrase, because the noun was followed by a Vital Noun Modifier.
I killed the snake with scales, which lived in the burrow behind my house.Since “with scales” cannot be moved elsewhere and it doesn’t cause ambiguity in meaning, we know that “which” modifies the snake.
Hope this helps x