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Grammar ABCs: C is for Comma

The comma is the most common punctuation mark inside sentences. Although they seem to be thrown by the wayside more and more these days, a simple comma can change the meaning of a sentence entirely as in: The July 2nd Thursday meeting will be held… Is it on July 2 or the second Thursday?

Commas are used to separate complete sentences connected by a coordinating conjunction: and, but, for, because. The bat is a nocturnal animal, and it sleeps during the day. I thought I could stay up all night, but I fell asleep about 4 a.m. The comma should not follow the and or but (such as The bat is a nocturnal animal and, it sleeps during the day.) The only time I let that one slide is occasionally in dialogue if the speaker is pausing for effect: “He is a completely self-centered man, and, he is a jerk.” However, there are better ways to show this.

Use a comma to set off most introductory phrases. A simple definition of a Phrase: A word group that lacks either a subject or a predicate or both: Fearing an accident, she drove fifteen miles per hour. Or In a panic, he rummaged through the drawers.

Use with a prepositional phrase, one that starts with words that take objects, such as: about, above, at, before, below, or as we used to say, to remember: over, under, around and through. Also use a comma before which but not before that.

A subordinate clause is usually used as an introductory element of a sentence and modifies a word or words in the main clause. It is usually set off by a comma: Although Beth had graduated at the top of her class, she still felt like the class dummy when it came to romance.

Beginning writers often have trouble with this type of clause and we see sentences that read like this: Galloping into town, the storm cloud followed us, spilling huge drops of rain. In this sentence the storm cloud is galloping into town.

The Grammar Gurus say you may omit the comma after a short subordinate clause or prepositional phrase if it does not create confusion: When snow falls our town closes. But using a comma in this instance is not wrong. Personally, I’m more comfortable putting one in. In this example, When Bob pulls Bill pushes could be confusing and you might start to read it as When Bob pulls Bill

Commas are used to set off nonrestrictive elements: The main house, Devon's design, is at the top of the hill. You can decide whether to use commas in such cases by removing the phrase. If the sentence still makes sense and is complete, you separate the phrase with commas.

Use commas in a series. The family needs clothing, food, and shelter. In fiction, you use a comma before the and. In journalism, you do not.

And you always use a comma in dialogue when addressing someone: Joe, I want you to come to my party.

These are just some of the major instances you use commas. Are you confused yet?

Does anyone have different examples of when and when not to use commas?


A native Montanan, Heidi M. Thomas now lives in Northwest Washington. Her first novel, Cowgirl Dreams, is based on her grandmother, and the sequel, Follow the Dream, has recently been released. Heidi has a degree in journalism, a certificate in fiction writing, and is a member of Northwest Independent Editors Guild. She teaches writing and edits, blogs, and is working on the next books in her “Dare to Dream” series.

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  1. Very useful! now I know why I never use the comma in a series as I went to college for Journalism. Guess I need to adjust now for fiction. I thought if you were consistent that you could use it either way ;) I was hoping! Thanks for the comma clarification.

  2. After last week's brouhaha about the demise and resurrection of the serial (or Oxford) comma, this is a timely post. Commas help make sentences make sense. My favorite example for the need for serial commas:

    I'd like to thank my parents, God, and Ayn Rand.

    Without the serial comma, it would read:

    I'd like to thank my parents, God and Ayn Rand.

    Not at all the same!

    Terry's Place
    Romance with a Twist--of Mystery

  3. Great post, Heidi. I find I do a lot of comma clarification in my editing.

    I'm curious: how would you punctuate the "July 2nd Thursday meeting will be held" example?

  4. Commas are enough to drive one nuts! And many times it is the publisher's style that makes the final decision.

    Kathryn, I would probably rewrite the sentence, but as it is, I would put a comma after July. The July, 2nd Thursday meeting.

    Happy Independence Day, All!!

  5. Good post Heidi--er--Good post, Heidi. May I quibble, though? You mention adding a comma after which but not after that. I agree, except writers often use which and that interchangeably. Isn't the more important distinction between restrictive and non-restrictive clauses? That also determines, for many of us, whether to use that or which.

  6. Great article Heidi. I at times still get confused with commas for coordinating conjunctions.

  7. Nice to all the information in one place. Thank You.

  8. I've been using a comma when in doubt. Hopefully, I can remember your tips and not use one when it's not needed.

    Morgan Mandel

  9. I try to keep up with such things, but still...thank heavens for copy editors!

  10. Good information. My daughter calls me the Comma Queen because she thinks I use too many commas in my writing. On the QT I think she uses too few.:-)

  11. I write reviews for a website called "The Portal," and I'm seeing more and more writing that is nearly bare of commas. I tend to be the comma splice queen, so I try to make sure I don't sprinkle the page with them, but reading paragraphs without commas is a little disconcerting.


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