USE A COMMA

1. With a coordinating conjunction to connect two independent clauses
   

   Betty is the homecoming queen, and Malik is the king.
   Either I will meet you in the lobby, or I will come to your office.
   DO NOT separate compound elements within a sentence.
   We plan to see a movie and then go to dinner.

2. To separate introductory phrases, words, or clauses from the main part of the sentence
   

   After the Vietnam War ended, a number of veterans were hospitalized.
   By the end of World War II, Europe was devastated.
   Fortunately, there has not been a third world war.

3. To separate nonrestrictive clauses, phrases, and appositives from the rest of the sentence
   

   The scout leader, overweight and out of shape, trudged up the hill.
   Mr. Riffell, who is a very good scout leader, is overweight and out of shape.
   DO NOT set off restrictive information with commas:
   Twain’s novel Huckleberry Finn is on the censored list.
   Students who plagiarize will be expelled.

4. To separate direct quotations from the phrase identifying the speaker
   

   John said, "The fishing is great in Perdido Lake."

5. To separate the names of smaller geographic units from the names of larger units
   

   Denver, Colorado, is called the Mile High City.

6. To separate items in a date. Omit the comma when just the month and year or month and day are given
   

   Kennedy was assassinated November 22, 1963, in Dallas, Texas.

7. To separate names of titles or degrees that follow the name
   

   Henry Louis Gates, Ph.D., will speak in the Commons on Tuesday.

8. To separate short, tightly, interrelated clauses in a series
   

   David phoned, Gretchen stopped by, and Phil left a message.

9. To mark allowable omissions of repeated words, especially verbs
   

   Your analysis is superbly written and vigorously argued; your grammar, appalling.

10. To provide clarity and prevent misreading, even if none of the other rules apply
    

    We left him, assured that he would fail.
    (We were sure that he would fail.)
    We left him assured that he would fail.
    (He was sure that he would fail.)

11. To separate three or more items or phrases in a series
    

    Golfing, swimming, and playing tennis are my favorite activities.
    We looked in the garage, in the greenhouse, and on the porch.

12. To separate a series of two or more adjectives not connected by a conjunction if the order of the adjectives can be reversed and still retain the same meaning
    

    Your roommate is a witty, intelligent person.
    DO NOT separate a series of adjectives which cannot be reversed:
    They are dedicated medical students.

13. To separate interrupters or parenthetical and transitional words from the rest of the sentence.
    

    Car sales representatives, on the whole, are not highly trusted individuals.
    Most of them, however, do try to act friendly and courteous.

14. To separate contradictory phrases from the rest of the sentence
    

    It was Carol, not Jeannie, who was elected queen of the prom.

15. To separate names used in direct address or other isolates such as yes, no, and thank you from the rest of the sentence
    

    Tell me, Ahn, whom did you vote for.
    No, I am not voting for myself.

16. To separate tag questions from the rest of the sentence
    

    You did that on purpose, didn't you?

17. To separate words and abbreviations that introduce an example or an illustration, including namely, that is, to wit, i.e., e.g., for example, and for instance
    

    Many of my friends, for example, Fred, Dean, and Anwar, like to golf.