by Cherie Tucker
We’ve looked at the trick of having “FANBOYS” stand for for, and, nor, but, or, yet, so to help you remember the comma rule; however, there is a tendency to err on the wrong side. When your sentence consists of two parts that could be separated into two stand-alone sentences, you need a comma before one of the FANBOYS to tell the reader that the first part is over and that the next part is on its way.
John went to the store in the pounding rain last night, but he forgot his wallet.
In that sentence, there could be a period after “night” to show that the first part was complete. The comma introduces the second half of the sentence that also could stand alone. (By the way, a sentence that is composed of two independent clauses is called a “compound sentence.”)
However, you don’t need a comma if one of one of the FANBOYS is not a divider in a compound sentence.
They brought gifts for all the boys but John.
He got a reward for his honesty.
I don’t care if you can sing or not.
There is a common but misguided belief that you always need a comma before “but.” Be careful before you add that little device that the word actually does what you think it is doing. See whether there is a subject and a verb in the words that follow before you add that single comma.
Please do add the comma before the “and” when you have items in a series. That little mark will ensure that the reader actually gets what you intended and doesn’t misread. Look at the difference between the two when that tiny mark is left out:
On board there were two serial killers, a priest and a baby.
On board there were two serial killers, a priest, and a baby.
When people are reading what you have written, you have control of their minds. Make sure that you use that power well.
Cherie Tucker, owner of GrammarWorks, has taught writing basics to professionals since 1987, presenting at the PNWA conference. She currently teaches Practical Grammar for Editors at the University of Washington’s Editing Certification program and edits as well. GrammarWorks@msn.com.