(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.
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.
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.