Remember that the two types of adjective clauses are identifying and nonidentifying. Identifying adjective clauses identify or give eessential information. Nonidentifying clauses give additional or nonessential information.
- I saw three movies last week. The movie that I liked best was "Captain America."
The adjective clause that I liked best is identifying because it says which movie I am talking about. If the clause were removed, the sentence would not make complete sense.
- The movie was "Captain America."
Therefore, the clause is necessary for the sentence to make sense.
- "Casablanca," which contains the famous song "As Time Goes By," is considered a film classic.
The nonidentifying clause which contains the famous song "As Time Goes By" adds more information about "Casablanca." The clause, however, is not used to identify. If it were removed, the sentence would still make sense.
- "Casablanca" is considered a film classic.
You do not actually pause when saying identifying clauses, so you do not enclose them in commas. Nonidentifying clauses have pauses before and after them, so they need commas. Here are some examples that you can review:
A person who needs others to become energized is an extrovert. (Identifying; no commas)
James, who comes alive when he feels comfortable with the people around him, is an extrovert. (nonidentifying; commas)
If you are unsure whether a clause is identifying or nonidentifying, try reading it aloud. The natural pauses made by your voice will help you figure out whether or not the clause needs to be enclosed in commas.
Exercise
Open the exercise to begin the activity. Follow the instructions in the document.