Friday, March 19, 2010

Confusing Commas

On the list of most common grammatical errors, misused commas rank right up there with misspellings and Mrs. Batchelder's rank perfume and hissing s.

(Sorry about that, I got a bit carried away. Every time I think about an English class I flash back to crazy old Mrs. Batchelder's high school English classroom. Then I throw up.)

So let's tackle commas in a way I hope will make sense.
First up: Serial commas

I prefer serial commas because they help reduce confusion. Serial commas are commas used after the next to last item in a list. Here's an example:

The patient complained of nausea, vomiting, and headache.


The comma after "vomiting" is a serial comma. You don't have to use one, but I do think they can be helpful in certain situations. So when in doubt, use it.
Next: Introductory phrases

Commas after an introductory phrase are rapidly losing their grip on us, and thank goodness. These are examples of introductory phrases:

  • After awhile

  • On the other hand

  • After the patient had gone to the bathroom


These phrases set up the rest of the sentence. Your English teacher probably smacked you upside the head if you didn't use a comma after an introductory phrase, but he had better not do that now unless you're writing for beginning readers. If you're writing for adults with a reading level over, say, the 10th grade, you needn't worry about sticking a comma after a beginning-of-the-sentence phrase. Use them only if leaving them out makes the sentence confusing, as in:

You know it seems odd that the window was left open like that.


The writer probably meant the sentence this way:

You know, it seems odd that the window was left open like that.


That kind of situation demands a comma.
Separating "sentences"

This is probably the toughest one for people to remember: When do you use a comma when you have what we call a complex sentence?

Generally if you have two complete sentences on either side of an and, but, or, nor, or any other what you wanna call yer conjunctions, use a comma. For instance, if we put these two sentences together…

Mr. Robinson knocked over the lamp.


AND


I ran into the room to find out what happened…


We would use a comma, as in:

Mr. Robinson knocked over the lamp, and I ran into the room to find out what happened.


Here, though, you would NOT use a comma:

Mr. Robinson knocked over the lamp and yelled for help.


Why no comma? Because "yelled for help" isn't a complete sentence.

Okay, class, that's enough for today.