This is a common problem I see in so many people’s writing. Grammar Girl gives a simple explanation: use that before a restrictive clause and which before everything else.
So what’s a restrictive clause?
It’s part of the sentence you can’t get rid of because it specifically restricts another part of the sentence.
Grammar Girl gives this example: “Gems that sparkle often elicit forgiveness.”
That sparkle restricts what kind of gems you are talking about. It specifies. Without “that sparkle,” you’d be saying all gems elicit forgiveness, which is another sentence entirely. (And you don’t generally use commas with that.)
However, with a nonrestrictive clause, you use which.
A nonrestrictive clause is one that can be removed without changing the meaning of the sentence.
Grammar Girl gives this example: “Diamonds, which are expensive, often elicit forgiveness.”
In this case, the sentence would have the same meaning even if you removed “which are expensive.” It would simply be, “Diamonds often elicit forgiveness.”
Next time, we’ll talk about the expendable which and the necessary that.
So what’s a restrictive clause?
It’s part of the sentence you can’t get rid of because it specifically restricts another part of the sentence.
Grammar Girl gives this example: “Gems that sparkle often elicit forgiveness.”
That sparkle restricts what kind of gems you are talking about. It specifies. Without “that sparkle,” you’d be saying all gems elicit forgiveness, which is another sentence entirely. (And you don’t generally use commas with that.)
However, with a nonrestrictive clause, you use which.
A nonrestrictive clause is one that can be removed without changing the meaning of the sentence.
Grammar Girl gives this example: “Diamonds, which are expensive, often elicit forgiveness.”
In this case, the sentence would have the same meaning even if you removed “which are expensive.” It would simply be, “Diamonds often elicit forgiveness.”
Next time, we’ll talk about the expendable which and the necessary that.