Just adding another quick AP Style tip to the collection. That and which are often confused. Here are some things to remember when you’re torn between the two.
- THAT should be used to introduce a restrictive clause.
- WHICH should be used to introduce a non-restrictive or parenthetical clause.
A restrictive clause is one that is essential to the meaning of a sentence – if it’s removed, the meaning of the sentence is altered.
A non-restrictive clause can be left out without changing the meaning of a sentence. Non-restrictive clauses are either in brackets or are separated by commas.
Changing the two words can change the meaning of the sentence.
My car that is yellow drives very fast.
My car, which is yellow, drives very fast.
The first sentence implies that I have more than one car. The second makes it seem like I have just one car.
Many people use which today in informal context:
- Who ate the cookies that I bought yesterday?
- Who ate the cookies which I bought yesterday?
The second technically isn’t correct; however, it’s often used in everyday speech.
An easy way to see if you need which or that in an unrestrictive clause is to remove the “which” and see if it still makes sense.
The sun, which is shining brightly, melted my ice cream.
The sentence still makes sense without the “which.”