The Comma                                    Back to Punctuation

 The comma is the most often used and misused of all the punctuation marks. People are confused about when to use it in a series, in an address, in quotations, etc. But its use is not actually that difficult if you observe a few simple rules.

Introductory Subordinate Clause
    Now that sounds like a mouthful to start with, doesn't it? Actually, it's not. A subordinate clause almost always starts with a word such as "when," "because," or "if." Such groups of words, even though they may contain a verb, cannot stand on their own as sentences and so must have an actual sentence (or independent clause) following them. A few illustrations should suffice:

When Bob and I took a camping trip, we forgot all the food and had to forage in the forest for berries and bird's eggs.

Because you have shown great courage in defending the weak against the forces of tyranny, we hereby award you the Nobel Peace Prize.

If you wanted to come along for the shopping trip, why didn't you say so?

Note that in each of the above examples, the subordinate clause cannot stand by itself because it makes no sense; we're waiting to find out what happens next. But if you took off the introductory word (also known as a subordinate conjunction), you would have a fine sentence.  Put in the comma and finish the thought.

Independent Clauses Joined by a Conjunction
    Again it sounds complicated, and again it's not. In fact, the first sentence I just wrote is an example of it. When you have two sentence that you want to join together, use a comma plus a conjunction such as "and," "but," "nor," "for," or "yet." Let's look at three examples:

I want you to come to my birthday party, and I won't take "no" for an answer.

She seems shy and withdrawn, yet she displayed great determination and forcefulness in yesterday's cross-examination.

Harold has not paid his rent on time in six months, nor has he repaid that $200 I lent him.

In the above cases, note that everything on both sides of the comma is a sentence, but the two sides are linked by the comma and a conjunction. By the way, you must NEVER link two sentences with just a comma. This is called a comma splice, and it is a federal offense. You could be looking at a long jail term! If you want to link two sentences with a mark of punctuation, that's one of the only jobs that a semicolon has.

Interjections
    Interjections are words or phrases that don't really do anything for the meaning of the sentence; they just take up a little space and act as a kind of throat clearing for the sentence to follow. Because they don't really act grammatically as part of the sentence, we set them off with commas, whether they come in the middle or at the beginning of the sentence.

Of course, you cannot be expected to know everything.

He was, in fact, an international spy.

On the other hand, it does seem like a good idea now that you've explained it.

Wow, look at that!

Notice that in each case above, we don't really need the phrases that are set apart. They do, however, serve as nice pauses or directional arrows, and they do the job of emphasizing or giving direction to the idea with which they're associated.

Parenthetical Elements
    Simply put, a parenthetical element is a word or a phrase that is not necessary for the grammar of the sentence, but it comes (usually in the middle) to limit or further define something else in the sentence. For example:

Sally, the girl in the blue dress, is my former babysitter.

Band practice, in spite of the fact that it lasts for two hours, is the most exciting part of my day.

Mr. Steen, considering the fact that he's as old as dirt, is surprisingly sharp for his age.

Noun of Direct Address
    This one is really easy. If you're talking directly to someone, set off that person's name with a comma.

John, is my brother here yet?

Mr. Smithers, I hereby submit my resignation.

Note that this simply avoids confusion. In the first sentence, without the comma, you'd think that John and the speaker are related, and the word "here" would be confusing at best.