And... do you know if you’re misusing them?
It seems like a lot of people think the two words are interchangeable when used as conjunctions, but they’re not.
Sometimes you might read a sentence and just feel that it is a little bit "off," without figuring out why. It could be because the writer should have used "that" but used "which" instead. Or - the other way around.
That and which are not the same.
- One introduces a restrictive clause.
- One introduces a non-restrictive clause.
Put another way…
One introduces a clause that is necessary to the meaning of the sentence.
One introduces a clause that could be left out without changing the meaning of the sentence.
Here are some examples:
The house that is on the corner of Main and Elm burned down last week.
What house burned down? The one on the corner of Main and Elm.
This is necessary to the sentence.
The house, which is on the corner of Main and Elm, burned down last week.
The house burned down last week, it’s location at Main and Elm is not necessary to the sentence.
The car that was parked in the driveway was stolen.
Which car was stolen? The one that was parked in the driveway. This is necessary to the sentence.
The car, which was parked in the driveway, was stolen.
The car was stolen. It isn’t necessary to tell where it was parked. That’s simply additional information.
Here’s a hint: “Which” is often in a phrase contained within commas.
The trick for remembering: If you're referencing a specific house, car, book, etc., use "that." (For people or pets, the word is "who.")
If the phrase is unnecessary but possibly interesting, use "which."
Oh - and if the phrase is not necessary and not interesting - just delete it entirely !