Booher's Rules of Business Grammar - Dianna Booher 2009
The alpha and the omega
Punctuation problems
ENCLOSING COMMAS COME IN PAIRS
Ding-dong. Zigzag. Yin-yang. Just as some words need to serve in pairs to convey their full meaning, enclosing commas come in pairs.
These enclosing commas set off nonessential information from the rest of the sentence. As a traffic signal, they tell readers, “Slow down and look out the window here; see the additional intriguing scenes off the main path as we pass.”
The common mistake with enclosing commas is that writers, like drivers, get in a hurry. They add the first comma of the pair and forget to add the final comma. (Maybe you have one of these people in your household: They open cabinet drawers and forget to shut them. They open packages and forget to discard the wrapping. They borrow things and forget to return them. They wear clothes and forget to put them in the laundry. Recognize a lifestyle here?)
Back to enclosing commas:
Incorrect:
Lancelot, my brother who lives in Ohio came to visit for the holidays.
Correct:
Lancelot, my brother who lives in Ohio, came to visit for the holidays.
Incorrect:
The client called Friday, March 21 about the contract.
Correct:
The client called Friday, March 21, about the contract.
Incorrect:
The clients asked about prices expecting them to be much higher than last year, but they were pleased to learn that we have not had an increase. (The first enclosing comma is missing.)
Correct:
The clients asked about prices, expecting them to be much higher than last year, but they were pleased to learn that we have not had an increase. (The second comma serves two purposes: it sets off the nonessential phrase and also joins the two independent clauses.)
Like parentheses, enclosing commas come in sets. Consider the word or group of words you’re setting off from the rest of the sentence. Then add the commas on both ends of that group of words. (Of course, if the second comma of the enclosing pair falls at the end of a sentence, use a period instead.)
Memory tip
Relate enclosing commas to bookends or parentheses. Use them as a set.