Rules for using commas
The comma is one of the most important tools of punctuation. if it is used correctly, it can clarify an otherwise confusing piece of writing. The following are some of the common rules and guidelines for using a comma.
Commas separate two independent clauses when used with a coordinate conjunction.
• The clock struck twelve, and I knew I was in trouble.
• No one could predict where he was going with that question, and no one wanted to answer it.
Commas separate words or items in a list.
• Mary stuffed the donuts, candy and brownies in her purse.
• He decided to take geography, geology and physics all in the same semester.
Note: No comma before the terminal “and,” unless an integral element of the series requires a conjunction.
• I had orange juice, toast, and ham and eggs for lunch.
Commas separate coordinate adjectives. They modify the same noun and could sensibly be separated by “and.”
• She described the intruder as a dark, beautiful woman.
Commas separate words or figures that might be misunderstood (but be careful about this use).
• What the problem is, is not clear.
Commas set off introductory material. (Coming before the main clause)
Prepositional phrase
• After all of the hardship, he was still unwilling to leave his home.
Participial phrase
• Having suffered heavy losses, the enemy withdrew.
Infinitive phrase
• To win games, the team decided to double its practice schedule.
Dependent clause
• If another strike takes place, the company has threatened to shut down the plant.
Commas set off words or phrases used as appositives. 
(An appositive is a word or phrase placed next to another word or phrase as an explanation.)
• John Smythe, the sole surviving son, now stands to inherit everything.
• Gary Hart, the former candidate, will speak at the meeting.
Commas set off non-essential (non-restrictive) clauses.
• Mary Jones, the woman standing on the corner, is my cousin.
• The latest entrant in the race is James West, who has served two terms in the office and one term in prison.
Commas set off parenthetical words or phrases.
• Connective adverbs - However, he found the load too heavy.
• Prepositional phrases - He, on the other hand, is a gentleman and a scalawag.
Commas set off the year in a complete date.
• The young man was born on Nov. 15, 2001, in Nashville.
Commas set off a state or country when a city or town name is used.
• She came here from Dublin, Ireland, when her father bought a toupee factory.
• His family moved to Tulsa, Okla., after his arrest for shoplifting a garden hose.
Note: Commas on both sides of the noun.
Commas set off nouns of direct address.
• She said, “You know, Joe, your marsupial is loose.”
• Susan, where did you hide my potato peeler?
Commas set off direct questions from attribution or other explanatory matter.
• “I can’t give you a statement until I finish this sandwich,” the judge said.
Commas set off age and address when used in identification format after names.
• Sam James, 32, 456 First St., was arrested at 2 a.m.
Do not use a comma when the clause is essential. (restrictive)
• The man who is standing on the corner is my cousin.
• The car that is stalled in the parking lot belongs to the nun.
Do not use a comma with a partial quotation.
(not an independent clause)
• He declared that the pie was “better than kissing.”
• He said that “anyone involved in the crime” would be charged.
Do not use a comma before a coordinate conjunction in a series.
• The flag is red, white and blue.
Do not use a comma between adjectives that are not coordinate. (The adjectives could not be separated by “and” and make sense.)
• That is a beautiful race horse.
• The knife has a sharp cutting edge.
Copyright © 2005 Jim Stovall www.jprof.com
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