That or which?

When you are deciding whether to use that or which in a sentence, you are making a choice between essential and nonessential clauses. Knowing how and when to use essential and nonessential cluases will clarify the meaning of your sentence. Which on you choose depends on what you want to communicate.

Essential clause

•       Essential clauses use that to include information that is necessary – or essential -- to understand the sentence. The use of that suggests there is a choice or a number of options.

Examples:

The sprinter chose the running shoes that gave her the greatest spring in her step.

(This suggests that the sprinter had an array of running shoes from which to choose, and she selected a particular pair that gave her a desired quality – spring.)

The food truck that is stationed at Niagara and Breckenridge streets on Wednesdays is under investigation.

(There are many food trucks that operate in the city, however it is the one that is at this particular intersection that is being investigated.)

Nonessential clause

•       Nonessential clauses use which, offset by a comma, for information that is not crucial – or nonessential -- to understanding the sentence

Examples:

The running shoes, which were given to her by Nike, were the ninth pair the sprinter tried on that morning.

(This lets the reader know where the sprinter got her shoes, which is interesting but not important to understand the meaning of the sentence and that is that she tried on nine pairs of running shoes before making her choice.)

Immigrants are welcome at West Side Community Center, which is on Barton Street.

(The point here is to tell the reader that the community center welcomes immigrants, regardless where it is located. There is only one and it is on Barton Street.)