Non-restrictive clauses are hard to teach! But they got much easier when I let Superman take over the job.
No kidding. All I did was play the introduction from the wonderful old Superman show (the black-and-white series from the 1950s, starring George Reeves).
Notice how the announcer’s voice drops after who (“and who, disguised as Clark Kent…”) and rises again after newspaper (“great metropolitan newspaper”).
It’s like clothespins, I would tell my students. One comma takes your voice down, and another comma brings it back up again.
Want another example? Try this famous line from Mission Impossible (but be sure to read it aloud – you’ll hear the commas):
Your mission, should you choose to accept it, is to intercept the enemy plane.
If you’d like to see a written version of this rule, click here and read Comma Rule 3. Happy punctuating!