Comma Rule 3 probably doesn’t sound like fun, but it is. It goes by some boring and very technical names (appositive, non-restrictive clause, interrupter). The basic idea, though, is easy: Use a pair of commas when your voice drops. One comma takes your voice down, and another brings your voice back up.
Here’s a familiar example from Mission Impossible:
Your Mission, should you choose to accept it, is to expose the enemy’s plot. COMMA RULE 3
Easy, isn’t it?
But wait! I’ve got an even better example. Click on the link for Superman!, and you’ll be able to hear a wonderful example of Comma Rule 3. Notice how the announcer’s voice goes down at the word who (comma) and comes up again at newspaper (comma). Turn on your speakers and listen for those two commas – it’s fun!
I never used any grammatical terminology when I taught Comma Rule 3 to my own students – it just intimidated them. Instead we played with voice-drop/rise sentences (which I always called “Superman” sentences), and students caught on quickly.
Here are some examples. I’ve marked the non-restrictive clause – sorry, the “Superman” – in red. But I’m betting you won’t need any extra help with these. (For best results, read them aloud, emphasizing the change in your voice):
Superman, disguised as Clark Kent, fights a never-ending battle for the American way. COMMA RULE 3
Although I’ll miss the best part of the trip, the tour of the White House, I’m looking forward to our visit to Washington. COMMA RULE 3
Writing a research paper, which I’ve always found difficult, is starting to get easier for me. COMMA RULE 3
George Reeves, who played Superman in the black-and-white series, was a terrific actor. COMMA RULE 3
You’ll find that often, but not always, the words who or which appear at the beginning of the interrupter (sorry – I meant the “Superman”). Try inventing some of these sentences yourself!
You can download a free handout with all three comma rules by clicking here.