Learning the difference between that and which is one of the biggest challenges of English grammar. They have similar functions and are used in similar sentences. But there is a difference, and it can change the meaning of the sentence.
I’m going to break down the grammar rules of these two words and provide plenty of examples along the way.
In summary, “that” is used for restrictive clauses and “which” is used for nonrestrictive clauses.
That vs. Which
The difference between that and which has to do with what type of clause it introduces.
- That — used for restrictive clauses. It changes the meaning of the sentence. Not used with commas.
- Which — used for nonrestrictive clauses. It does not change the meaning of the sentence. Used with commas.
Now here’s how I like to think of it: That is used when referring to one particular thing out of multiple similar things. Which is used when there is only one thing (or group of things).
Still not sure what all that means? Keep reading.
What is a Clause?
Clauses are phrases that have both a subject (noun/noun phrase) and a predicate (verb/verb phrase).
Examples of clauses
- I ate pizza
- As I was walking
- Who went to the store
- That disappeared last week
There are many different kinds of clauses, but for our purposes, it’s important to know that some clauses are restrictive, which means they change the meaning of a sentence, and some are nonrestrictive, which means they do not change the meaning of a sentence.
That introduces restrictive clauses and which introduces nonrestrictive clauses — with commas.
If all this sounds like gobbledygook, don’t fret. It will be a lot clearer when we start looking at examples.
That and Which Compared — with Examples
According to the Purdue Online Writing Lab, a restrictive clause means that the information in the clause is necessary to understand the preceding noun. This is when we use the word that.
Let’s look at some examples.
That vs. Which Example 1
Here is an example of using “that” and “which” and how they differ.
- The apple that has a worm in it is dangerous to eat.
- The apple, which has a worm in it, is dangerous to eat.
What is the difference in meaning between these two sentences?
In sentence 1, it is clear that there are multiple apples, and the one that has a worm in it is the one that is dangerous to eat. This is a restrictive clause that points us to exactly which apple we should avoid.
Sentence 2, on the other hand, implies that there is only one apple, and the nonrestrictive clause “which has a worm in it,” is not necessary to the sentence. (Though we still might like to know! Yuck!)
That vs. Which Example 2
Let’s compare two more sentences.
Marcy’s dress that has pockets was a gift from her sister.
The phrase “that has pockets” is a restrictive clause because it is necessary to understand the noun dress. From this sentence, we can infer that Marcy has multiple dresses and only the one that has pockets was a gift from her sister.
What if we used which? Well, we’d need to put commas around the clause, and it would look like this:
Marcy’s dress, which has pockets, was a gift from her sister.
This time, “which has pockets” is non-restrictive, and the sentence will remain intact if we take it out: Marcy’s dress was a gift from her sister.
How does switching from that to which change the meaning of the sentence? Well, when we use which, we imply that Marcy has only one dress, and whether it has pockets is unnecessary information to the sentence. In the first example, our restrictive clause makes the subject “Marcy’s dress that has pockets,” whereas the second sentence leaves the subject as “Marcy’s dress,” and the unrestrictive clause adds the detail of pockets.
That vs. Which Example 3
Finally, let’s imagine that I’m taking you to my favorite brunch spot.
I could tell you:
The pancakes, which come with strawberries, are delicious.
Or perhaps I tell you:
The pancakes that come with strawberries are delicious.
What would you glean from each of these statements?
Well, the first statement implies that there’s only one kind of pancake, and they come with strawberries.
The second statement, however, implies that there are multiple kinds of pancakes, but I think that the ones that come with strawberries are delicious.
Use That and Which Like a Pro
So there you have it, the difference between that and which.
Do you have more grammar questions? Check out our other blog posts, like this one on When to Use a Comma before “and.”
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