Writers Workshop: Writer Resources
Grammar Handbook: Restrictive and Nonrestrictive Clauses
A modifying clause can be either restrictive or nonrestrictive.
A restrictive modifying clause (or essential clause) is an adjective clause that is essential to the meaning of a sentence because it limits the thing it refers to. The meaning of the sentence would change if the clause were deleted. Because restrictive clauses are essential, they are not set off by commas.
- All students who do their work should pass easily.
- The car that I want is out of my price range.
- The gas company will discontinue our service unless we
pay our bills by Friday.
A nonrestrictive modifying clause (or nonessential clause) is an adjective clause that adds extra or nonessential information to a sentence. The meaning of the sentence would not change if the clause were to be omitted. Nonrestrictive modifying clauses are usually set off by commas.
- Edgar Allan Poe, who wrote "The Raven," is a great American poet.
- Puerto Rico was a Spanish colony until 1898, when it was ceded to the United States.