Punctuation: Different Punctuation marks: Commas

Use commas:

1. To mark the breaks between items in a series.
EXAMPLE: The alumni's spirit was evident in the loud cheers, the spirited songs, and the rousing music.
For the best results, be sure to include flour, eggs, and butter.
NOTE: If items in a series already contain commas, then use semicolons to separate the main elements.

EXAMPLE: The winter weather in Seattle was rainy, windy, and cold; the driving was fast, furious, and courteous, yet all was forgiven with a glimpse of the mountains.
NOTE: There is no hard and fast rule regarding the comma before the "and" in a series. Some prefer to omit the comma. Others feel that using the comma makes the reading clearer. In any case, be aware of your professor's preference and, above all, be consistent in your use.



2. Before the coordinating conjunctions and, but, so, for, yet, or, nor to join independent clauses.
EXAMPLES: None of the partners wants to dissolve their assets, nor do any agree to the bankruptcy proceedings arranged by the attorney.
The telephone rang many, many times, so John answered it even though he was at Tiffany's house.



3. To mark the end of a long (four or more words) introductory element.
A. Use commas after long introductory prepositional phrases, but usually not after short phrases.

Examples: In a little cabin at the edge of the woods across the river, lives an old man with his twenty-seven cats. (After the succession of four introductory prepositional phrases, a comma is needed to separate them from the rest of the sentence.)
In the morning I will call my boss. (A short prepositional phrase needs no comma after it.)

B. Use commas after introductory clauses unless they are quite short or have no special emphasis.

Examples: After Sue had finished playing, the piano was rolled offstage. (Note that without the comma, you might tend to read this sentence, "After Sue had finished playing the piano..," which would be very confusing.)
Whenever I see her, I admire her courage in the face of adversity.
Considering how much she has already learned, Marcie was surprised at how poorly prepared she was for her new position.



4. To separate an interruption from the rest of a sentence.
EXAMPLES: The crowd, however, was cheering after the scoring drive despite the flag on the field.
The winter's chill, despite the shining sun, was enough to bring the children home early.



5. To separate quoted words from the rest of a sentence.
EXAMPLE: "The whole idea is ludicrous," Jonathan thought after hearing the proposal.



6. To separate items in an address or date.
EXAMPLES: Her address is 1916 First Avenue North, Apt. 604, Austin, Texas, for the rest of the semester.
He was born on June 26, 2004, in the middle of a heat wave.



7. To set off non-restrictive clauses (a group of words that are not essential to the meaning of the sentence).
EXAMPLES: Mr. Hoffer, whose family lives in Germany, will be our guest this weekend.
Mr. Johnson, whose son attends the University, is our friend.



8. To set off an appositive (a group of words renaming the subject).
EXAMPLE: Jen, a computer security specialist, completed her third 100-mile cycling event in a month