Restrictive and Nonrestrictive Adjective Clauses

How to tell the difference between the two types of clauses

An adjective clause functions almost exactly like a solo adjective, to modify a noun. Adjectival clauses are dependent clauses, and usually begin with a relative pronoun (which, that, who, whom or whose) or a relative adverb (where, when, and why). 

There are two main types of adjectival clauses: nonrestrictive and restrictive. Here's a little bit about how to distinguish between the two. 

Nonrestrictive Adjective Clauses

An adjective clause set off from the main clause by commas is said to be nonrestrictive.

Here's an example:

Old Professor Legree, who dresses like a teenager, is going through his second childhood.

This who clause is nonrestrictive because the information in the clause doesn't restrict or limit the noun it modifies ( Old Professor Legree). The commas signify that the adjective clause provides added, not essential, information. This practice is consistent with Comma Guideline #4: "Use a pair of commas to set off interruptions."

Restrictive Adjective Clauses

On the other hand, an adjective clause that is restrictive should not be set off by commas.

An older person who dresses like a teenager is often an object of ridicule.

Here, the adjective clause restricts or limits the meaning of the noun it modifies ( An older person). A restrictive adjective clause is not set off by commas.

So to review, here are the basic rules. An adjective clause that can be omitted from a sentence without affecting the basic meaning of the sentence should be set off by commas and is nonrestrictive.

An adjective clause that cannot be omitted from a sentence without affecting the basic meaning of the sentence should not be set off by commas and is restrictive

Practice: Identifying Restrictive and Nonrestrictive Clauses

For each sentence below, decide if the adjective clause (in bold) is restrictive or nonrestrictive.

When you're done, check your answers at the bottom of the page.

  1. Students who have young children are invited to use the free daycare center.
  2. I left my son at the campus daycare center, which is free to all full-time students.
  3. John Wayne, who appeared in over 200 movies, was the biggest box-office attraction of his time.
  4. I refuse to live in any house that Jack built.
  5. Merdine, who was born in a boxcar somewhere in Arkansas, grows homesick every time she hears the wail of a train whistle.
  6. My new running shoes, which cost more than a hundred dollars, fell apart during the marathon.
  7. I lent some money to Earl, whose house was destroyed in the flood.
  8. The thing that impresses me the most about America is the way parents obey their children.
  9. A physician who smokes and overeats has no right to criticize the personal habits of his patients.
  10. The beer that made Milwaukee famous has made a loser out of me.

Here are the answers to the exercise:

  1. restrictive
  2. nonrestrictive
  3. nonrestrictive
  4. restrictive
  5. nonrestrictive
  6. nonrestrictive
  7. nonrestrictive
  8. restrictive
  9. restrictive
  10. restrictive