Hey there, writer!
Today’s Grammar Time is about correctly using the relative pronouns that and which. Many people tend to assume that these words are always interchangeable, but this isn’t the case. That and which are commonly confused, and knowing the difference boils down to understanding defining and non-defining clauses.
Defining vs. Non-Defining Relative Clauses
Defining and non-defining clauses are kinds of relative clauses, which are clauses that provide additional information about the subject. For example:
- The heart surgeon, who had already saved many lives, was able to operate successfully.
The phrase “who had already saved many lives” gives you a little more information about the heart surgeon (the subject).
Defining Relative Clauses
A defining relative clause provides a piece of essential information about the subject. The information cannot be removed without changing the meaning of the sentence. If the sentence requires the clause, you’ll usually use the word that to connect it, as this word points to crucial information. Take a look at the following example:
- The Amazon office that does orientation is located in Seattle.
In this case, a comma is not needed because the relative pronoun that points specifically to the Amazon office that does orientation.
Non-Defining Relative Clauses
A non-defining relative clause, on the other hand, provides more information about a subject but does not define what is being talked about. In this case, the word which will be used to refer back to the subject or object of the sentence and will be offset by commas.
- Paris, which is a popular tourist destination, is beautiful in the spring.
As you can see, the information within the commas can be removed without changing the point that Paris is beautiful in the spring.
A Quick Way to Remember
The hard-and-fast rule is that if the sentence in question doesn’t require the clause, use the word which. If the clause is necessary to the meaning, use that. For example:
- Our favorite restaurant, which has a buffet, is located in Orem.
- Our favorite restaurant that has a buffet is located in Orem.
These sentences look the same, but they say different things. The first one simply states that our favorite restaurant is located in Orem, and it just happens to have a buffet. When the clause is removed, the meaning is still clear: “Our favorite restaurant is located in Orem.” The second example, on the other hand, specifies that our favorite restaurant with a buffet is located in Orem (but it might not be our overall favorite restaurant).
The Sandwich Bag Rule
The word which can be thought of as a sandwich bag. You can take the sandwich (or the non-defining relative clause) out of the sentence (the sandwich bag) without ruining the bag.
Referring to Another Clause
Another instance in which you can use the relative pronoun which is when you refer to all the information in the beginning of a sentence rather than just a single noun. Take the following, for instance:
- I aced all of my math tests this week, which came as quite a shock.
Which is used in non-defining relative clauses or when referring to the whole clause, not the noun alone, while that is used in defining relative clauses.
Hopefully this has helped you better understand the differences between defining and non-defining clauses and when to use which and when to use that. Until next time!