3.2: Comma—Six Main Uses

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Frost & Samra et al.
Kellogg Community College

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1. To separate items in a series.

I need to buy milk, bread, chicken, and potatoes for dinner. (Notice that the comma before the “and” is required.)

2. To set off introductory material.

After several days, the fish in the refrigerator began to smell.
Impatiently, the young mother jerked her son away from the store window.

3. On both sides of words that interrupt the flow of thought in a sentence.

The children, clean and dressed, were ready to meet the company.
Mary Jones, who won the lottery, is my new best friend.

4. Comma between complete thoughts connected by a coordinating conjunction.

Make sure that you have two complete thoughts. If you do not have a subject on both sides of the conjunction, no comma is needed. (Notice that the previous sentence made use of comma rule 2.)
John and Mary used to live in Annapolis, but now they live in Seattle.

5. Comma with direct quotations.

The exact words out of the speaker’s mouth are put in quotations and preceded by a comma.
I hate it when paratroopers ask, “Is your chute folded correctly?”

6. Comma with everyday material.

I think, Leo, that you are a wonderful person. Wendy, can you show me how to make donuts? [ addressing people ]
We hit a deer on December 12, 2012, and again on January 1, 2013. [ dates ]
My mother lives in Pittsburgh, Pennsylvania. Her address is 2910 Weston Avenue, Gibsonia, Pennsylvania 15229. [ addresses ]
Dear Titus, / Sincerely, Kim [ openings and closings of letters ]
Last year, Lou lost over $24,000 at FireKeepers Casino. [ numbers ]

Exercise $\PageIndex{1}$

The following paragraph is missing five commas. Using the previous rules, consider where you would (and wouldn’t) add commas to individual sentences.

Many people would not view the Industrial Revolution as a time of poverty. While the revolution was good for the economy of the United States it was not a solution for poverty or the poor. It changed people’s lives and although they were more mobile the impoverished moved from one poorhouse to another to find work. Life became easier for many citizens of course but factory life was often grueling and dangerous. The effects are still lingering today and movement between social classes is difficult for many to achieve.