Restrictive and nonrestrictive words phrases and clauses

Editor Kory Stamper takes another look at a recent question.

In our last blog post, you will remember that one of our readers asked a question about the difference between these two sentences:

The old lady who was injured in the accident is now in the hospital.
The old lady who is now in the hospital was injured in the accident.

We discussed modifying clauses and their placement, but these two sentences give us a chance to talk about two specific kinds of modifying clauses: restrictive clauses and nonrestrictive clauses.

A restrictive clause identifies the noun or verb that precedes it and is needed to understand which person or thing is meant:

I preferred the soprano who sang last year.
The old lady who was injured in the accident is now in the hospital.

A nonrestrictive clause adds information about something but is not needed to understand which person or thing is meant:

My uncle, who I haven't seen in years, works for the government.
The old lady, who is now in the hospital, was injured in the accident.

As you can see, nonrestrictive clauses are separated from the rest of the sentence by one or two commas; restrictive clauses are not separated from the rest of the sentence by commas.

There are a few other interesting usage points when considering whether a clause is restrictive or nonrestrictive. Clauses that begin with which and refer to the entire main clause are nonrestrictive:

She ignored my advice, which surprised me.

When a restrictive clause begins with a relative pronoun or relative adverb, the pronoun or adverb can often be omitted:

The reason (that) he gave wasn't convincing.
That was the year (when) I went to Romania.

But this is never possible in nonrestrictive clauses, or in clauses where the pronoun is the subject:

CORRECT: He had a magazine, which he had finished reading.
INCORRECT: He had a magazine, he had finished reading.

CORRECT: They're the relatives who raised me.
INCORRECT: They're the relatives raised me.

In the two sentences we looked at last time, the first sentence ("The old lady who was injured in the accident is now in the hospital") uses a restrictive clause: there many be many old ladies in the hospital, but the one we are talking about now is the old lady who was injured in the accident. The second sentence ("The old lady, who is now in the hospital, was injured in the accident") uses a nonrestrictive clause: the main point of the sentence is that the old lady was injured--that she is in the hospital does not clarify which old lady we are talking about as there may be many old ladies at the hospital, but there is presumably only one old lady who was injured in the accident.

The suspect in the lineup who has red hair committed the crime.

Note how the subject "suspect" in this sentence is restricted in two ways: we know that this suspect is both in the lineup and has red hair. As a result, we know that the other suspects, who are not in the lineup, could not have committed the crime. Moreover, of those suspects in the lineup, we know that the one suspect in the lineup with red hair committed the crime. If there were more than one suspect in the lineup with red hair, the above usage would be incorrect because it implies a different meaning.

Correct Nonrestrictive Use:
 

The suspect in the lineup, who owns a red car, committed the crime.

In this example, the restrictive clause "in the lineup" tells us that of all possible suspects in the world, the one who committed the crime is in the lineup. However, while the nonrestrictive clause "who owns a red car" tells us something about the suspect, it does not foreclose the possibility that there are several different suspects in the lineup with red cars. The car color may tell us something useful, but it does not restrict us to only one possibility.

2.  When choosing between "that" and "which," use "that" to introduce a restrictive clause and "which" to introduce a nonrestrictive clause. Although some writers use "which" to introduce a restrictive clause, the traditional practice is to use "that" to introduce a restrictive clause and "which" to introduce a nonrestrictive clause. When writing a restrictive clause, do not place a comma before "that." When writing a nonrestrictive clause, do place a comma before "which."

The store honored the complaints that were less than 60 days old.

Correct Nonrestrictive Use:
 

The store honored the complaints, which were less than 60 days old.

These sentences have different meanings as well as different punctuation. In the restrictive sentence, the store honored only those complaints less than 60 days old, but not those over 60 days old. In the nonrestrictive sentence, the store honored all the complaints, all of which were less than 60 days old.

3.  Place proper punctuation around nonrestrictive clauses, but do not place punctuation around restrictive clauses. When a nonrestrictive clause appears in the middle of a sentence, place commas around it. When a nonrestrictive clause appears at the end of a sentence, place a comma before it and a period after it. Do not punctuate restrictive clauses.

The 1964 Ford Mustang, which propelled Lee Iacocca to the top of the automobile industry, is now considered a classic.

Correct Punctuation of Nonrestrictive Clause:
 

The credit card is in my wallet, which you can find in the kitchen drawer.

Correct Punctuation of Restrictive Clause:
 

The boat that sailed on October 25 is the one to which we referred in the contract.

What are restrictive and nonrestrictive clauses examples?

What is a restrictive phrase example?

What is a non restrictive phrase or clause?

What is the difference between restrictive and nonrestrictive words?