In this lesson, we are going to look at two adjective clauses: restrictive and nonrestrictive. Each plays an important role in our understanding of English grammar, so let's define them and look at examples so there are no doubts.
Restrictive vs. Nonrestrictive
How can we tell the difference between a restrictive adjective clause and a nonrestrictive adjective clause? A restrictive adjective clause is a clause that is necessary in order to identify the noun it modifies. It gives the reader information that is essential or necessary to the understanding of the sentence, and it does NOT use commas. A nonrestrictive adjective clause is one that is not necessary in order to identify the noun it modifies. It provides information that is not essential to the understanding of the sentence, and it DOES require the use of commas.
So, now you understand the definitions, but there is just a bit more to talk about in order to use adjective clauses when you write or to recognize them easily.
Restrictive Clauses
In order to fully understand how restrictive clauses work, it is important to look at examples and discuss what makes them restrictive. Consider these examples:
The girl who has the blue eye shadow is the one I want to help me with my makeup.
In this case, it is clear that the clause, 'who has blue eye shadow' is restrictive because it is necessary to the sentence. We understand that in this sentence, it is the girl who has the blue eye shadow who can help. Both conditions must apply in order for the statement to be true. The girl must have blue eye shadow, and she is the one to help with the makeup.
The situation that makes me feel the best is when I am in control of what is happening.
In this example, 'that makes me feel the best' is the restrictive clause, and we can see it is necessary to our understanding of the sentence.
Note: Usually when we have a choice between 'that' or 'which,' we should choose that to introduce restrictive clauses and which to introduce nonrestrictive clauses. It is also interesting to note that when using 'that' for restrictive clauses, you do NOT use a comma before 'that,' but when using 'which,' you DO place a comma before 'which' in nonrestrictive clauses.