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Commas (Eight Basic Uses)
To better understand the use of the comma, begin by learning the following eight basic
uses:
1. USE A COMMA TO SEPARATE INDEPENDENT CLAUSES.
Rule: Use a comma before a coordinating conjunction (and, but, yet, so, or nor, for) when it joins
two complete ideas (independent clauses).
1. He walked down the street, and then he turned the corner.
2. You can go shopping with me, or you can go to a movie alone.
2. USE A COMMA AFTER AN INTRODUCTORY CLAUSE OR PHRASE.
Rule: Use a comma after an introductory clause or phrase. A comma tells readers that the
introductory clause or phrase has come to a close and that the main part of the sentence is about
to begin.
1. When Evan was ready to iron, his cat tripped on the cord.
2. Near a small stream at the bottom of the canyon, park rangers discovered a gold mine.
3. USE A COMMA BETWEEN ALL ITEMS IN A SERIES.
Rule: Use a comma to separate each item in a series; a series is a group of three or more items
having the same function and form in a sentence.
1. We bought apples, peaches, and bananas today. (series of words)
2. Mary promised that she would be a good girl, that she would not bite her brother, and that she
would not climb onto the television. (series of clauses)
3. The instructor looked through his briefcase, through his desk, and around the office for the lost
grade book. (series of phrases)
4. USE COMMAS TO SET OFF NONRESTRICTIVE CLAUSES.
Rule: Use commas to enclose clauses not essential to the meaning of a sentence. These
nonessential clauses are called nonrestrictive. Clauses which are essential are called restrictive.
Both restrictive and nonrestrictive clauses may begin with a relative pronoun (such as who, whom,
whose, that, which). A relative pronoun refers to the noun or pronoun that precedes it.
1. Steven Strom, whose show you like, will host a party next week. (nonrestrictive)
2. John, who spent the last three days fishing, is back on the job again. (nonrestrictive)
3. The gentleman who is standing by the fireplace is a well-known composer. (restrictive)
5. USE A COMMA TO SET OFF APPOSITIVES.
Rule: An appositive is a noun or noun phrase that renames a nearby noun. Appositives offer
nonessential information. Nonrestrictive appositives are set off with commas; restrictive
appositives are not.
