As you can see from the sentence in the headline, which appears in Hacker and Sommers’s Rules for Writers (7th edition), a missing comma can make for some pretty funny reading—even if we didn’t intend to be amusing.
For some people, though, commas are no laughing matter. Not long ago a friend of mine cried as she told me her tale of comma woe (which involved a mean-spirited professor, a red pen, and a classroom full of laughing students).
The rules regarding comma use are finite and are not too difficult to learn, though. Below are a few rules you might find especially helpful:
Use a comma between all items in a series (known as the Oxford, or serial, comma). Although some argue that a comma before the last item in a series is not necessary or, as might be the opinion of a newspaper editor, takes up too much space, I use it because it makes clear what otherwise might be confusing.
- CORRECT: I love my parents, Lady Gaga, and Humpty Dumpty (from Grammarly).
- UH-UH: I love my parents, Lady Gaga and Humpty Dumpty.
Use a comma before a coordinating conjunction (think FANBOYS—for, and, nor, but, or, yet, so) ONLY when what follows that conjunction is a complete sentence with a subject and a verb (an independent clause).
- CORRECT: I will cook, and I will also do the dishes.
- UH-UH: I will cook, and will also do the dishes.
Use a comma after an introductory clause or phrase.
- CORRECT: After taking a very long bus and train ride, my cousin said she was tired and wanted to go to bed.
- UH-UH: When Irwin was ready to iron his cat tripped on the cord (from Rules for Writers, 7th edition).
- EXCEPTION: You can omit the comma if the clause or phrase is short and the sentence will not be confusing without it. (Example—For once she was happy to see him.)
So now you know.