This post will require more than a minute (or one post), but I think it’s worth it, because commas are so seldom used correctly.
I overuse commas. I know the rules; however, sometime over my lifetime, I developed the unfortunate habit of typing a comma “,” every time I paused while writing a sentence. Too bad I did not also develop the habit of finding all these extra commas during editing. Since I’ve discovered that most editors don’t know when to remove commas either, many of these superfluous keystrokes end up in my writing.
Just as bad (in my opinion) are those who underuse commas. Their sentences are devoid of all but the most obvious pauses, requiring the reader to go back and re-read sentences correctly once they figure out the proper construction.
So, when are commas required, and when are they not?
Introducing Independent Clauses
Commas are required when used to separate independent clauses when they are preceded by any of the following conjunctions: and, but, for, or, nor, so, yet. Not sure what an independent clause is? Simple, it is a part of a sentence that could stand by itself. Here are some examples.
- Dave went to the store, but he forgot to buy the milk.
- I love you, and that is why I must kill you.
- It is a simple construct, yet many writers get it wrong.
In the above examples, the independent clauses are shown in italics. You can see that in each of the sentences, the italicized clause could be a sentence by itself. In these instances the comma and conjunction serve the same function as a semi-colon “;”. For instance, the first example sentence could be rewritten as: “Dave went to the store; he forgot to buy the milk.”
After Introductory Phrases, Clauses, Words
This is where I see commas omitted the most. Commas are required after introductory clauses that precede the main clause. Again, there are trigger words to remember: after, although, as, because, before, if, since, when, while.
- When entering the building, please badge in.
- Before you go, please repay my money.
There also common phrases that are triggers, but these take a bit more thought:
- Participial phrases (adverbs derived from participle forms of verbs):
- Having done this before, I found it easy.
- Burying his head in his hands, the boy wept.
- After yes, no, well, so, and however:
- Yes, I have no bananas.
- Well, if you insist.
- So, my day started out well; then she showed up.
Two or More Coordinate Adjectives
When two or more adjectives describe the same noun, use a comma between the adjectives (but not the adjective and a noun). Coordinate adjectives are easy to determine because they would makes sense if you changed their order. They are independent of each other, rather than forming a phrase. Examples:
- The long, sleek, car was immaculate.
- The quick, brown fox jumped over the lazy dog.
- His black flannel socks were warm. (Not coordinate, as you would likely not say, “His flannel, black socks were warm.”
Use to Set off Non-Essential parts of a sentence
These are clauses, phrases or words that occur in the middle of a sentence, but which aren’t required to understand the sentence. They are similar to parenthetical “( )” phrases in that if they are moved elsewhere in the sentence (or deleted) it would still make sense. Examples:
- Tom went to the bar, carrying his dead parakeet, and had a drink.
- Bob, on the contrary, is an idiot.
- Wrong: Handsome men without money don’t have a chance. (Here, if you delete “without money” the meaning of the sentence changes.)
There are more cases, but I’ll tackle those tomorrow. See ya!