Are there too many commas in your writing? Not enough? Where do you need them and when? “Comma confusion” is one of the most common grammatical problems I find in manuscripts. Here are some quick tips to help you determine whether a comma is really necessary — and if so, why and where.
One way to help identify “right” and “wrong” punctuation is through substitutions. If you can substitute the item for which a bit of punctuation is “standing in for,” you have the correct punctuation. If you can’t… you don’t.
Let’s start with commas and “run-on sentences.” A “run-on” sentence is one in which several complete phrases are strung together with commas. Each phrase is in itself a complete sentence. But when they are strung together, what they form is not a complete sentence.
Another substitution you could make is using the word “and”:
Another common comma misusage is to have the impression that “I just know a comma is needed here somewhere, but I’m not sure where, so, I’ll, just put in a couple and, hope for the best.”
Let’s start with the “period/comma” substitution test and see what happens:
After that, well, it’s pretty obvious that you don’t have complete sentences. So start taking out periods and see what happens:
Now a quick digression: Some people object highly to starting a sentence with “but” or “and.” I am not one of them. I don’t think it should be done often, but it can be done — as it does. create a “complete thought.” An alternative is to use “however,” but this can create a more complicated sentence and isn’t always what you want. “However” will nearly always need to be followed by a comma; “but” does not:
One of most common uses of a comma is to set off a “dependent clause.” A dependent clause is a part of a sentence that can’t live on its own. It needs life-support. It generally does not have its own subject, or quite often even its own verb, like that clause I just inserted. It doesn’t make sense without what went before.
Without commas, a dependent clause contributes to a run-on sentence that is very hard to understand. The commas tell you “hey, listen up, new thought or idea coming here!” The primary problem with dependent clauses is forgetting to “close” the comma. If a dependent clause occurs within a longer sentence, it must open and close with a comma.
You can quite easily identify a dependent clause with the “period” substitution — you’ll instantly see that you don’t have complete sentences. But you can’t expand on this substitution by inserting an “and” — so now what? Try the next item on your substitution menu: The parenthesis. A dependent clause can be set off with a parenthesis and still be correct:
Once you identify a clause that can be set off with parentheses (which clearly must be opened and closed), it’s much easier to determine where you need to put that second comma. You could also choose to leave the parentheses, or you could use dashes (which also have to be opened and closed):
The Apposite Phrase
One common area of “comma confusion” is the apposite phrase. An apposite phrase is a type of dependent clause that further defines the subject (or object) of a sentence. It is an element of description that may add to the information that you are providing, but that could be removed without badly damaging the sentence. Sometimes it is hard to distinguish between an apposite phrase and an ordinary “clarification” or bit of description.
One of the most common places in which there is confusion is over things like introductions, like the following:
“John, this is my wife, Mary.”
This is not an apposite phrase because it is suggesting that the speaker has more than one sister (perhaps Joan and June), and the speaker is therefore clarifying not only that this is his sister, but which sister it is. If you put a comma here, you would be implying that the speaker only has one sister, named June. Without the comma, you are indicating that the speaker may have several sisters and you must clarify which it is.
An apposite phrase is one that can often be dropped without damaging the structure of the sentence or badly obscuring the meaning. Thus, if you write: “British novelist Jane Maladroit…” you do not need a comma between “novelist” and “Jane,” because you can’t actually drop the words “Jane Maladroit” without badly obscuring the meaning of the sentence. There are many British novelists; there is only one Jane Maladroit. So, as with the “my sister June” example, you need to keep the name in the sentence to make the sentence clear.
However, you could write: “Jane Maladroit, British novelist..” as an apposite phrase (with the commas), because in this case, you are saying Jane Maladroit = a British novelist. The words “British novelist” are an added bit of definition to the subject “Jane Maladroit “, and while they’re helpful, they could be removed without damaging the sentence too badly. You could write, “Jane Maladroit won the prize,” and the reader would understand the sentence and come away with the information needed. But you couldn’t say “British novelist won the prize” and provide nearly as much information.
So here’s a quick and easy way to test whether something is an apposite phrase or not. Can you put in an “equal sign”?
“My wife = Mary” – you probably only have one wife (fewer if you are female).
“My sister = June” – this works only if you have only one sister
“Our sister site = LoadsofSisters.com” – this works if you have one sister site.
“Jane Maladroit = British author” – this works if Jane is a British author.
“John Smith’s new book = Understanding the Comma” – this is a bit “iffy” but works if John Smith has only brought out one new book recently.
Here are some phrases where you can’t put in an equal sign:
“My sister > June”
Now, one more bit of confusion: You can sometimes avoid the whole comma issue by putting the apposite phrase before the subject:
- British novelist Jane Maladroit won the prize.
- American writer Moira Allen wrote a lengthy treatise on apposite phrases and had the nerve to call it “short.”
- British writer Anne Nonymus often wished American writer Moira Allen would shut up already.
In these cases, the phrase really stands as an adjective (which is, at rock bottom, what an apposite phrase is, and that was one). It can’t always be done, but one way to test whether something is an apposite phrase and needs to be set off by commas is by testing to see if you can turn it around this way and retain the same meaning.
Apposite phrases can in fact be very long. Think of them as very long adjectives:
And that brings me to the semicolon…
I know, I know: A semicolon is not a comma, even though it rather looks like one. However, when one is confused about where to put commas, one is often tempted to try to slap in a semicolon and hope it will solve the problem.
The best way to understand a semicolon is to realize that it really is a substitute for a period. A semicolon is the “legal” way to join two standalone sentences. If you do it with a comma, you have an incomplete sentence. If you do it with a semicolon, you have a complete sentence. Could you have done it with that last sentence above? Try it:
For a semicolon to be used, both clauses must stand alone:
Another use of the semicolon is to separate lists that include lots of commas, hence:
Commas and Other Punctuation
A final source of “comma confusion” is where to place commas in conjunction with other forms of punctuation, such as quotes, parentheses, etc. Again, substitutions can often help here.
A mistake I often see is to place a comma before a dependent parenthetical clause, like this:
Moira Allen is the editor of Writing-World.com and the author of more than 300 published articles. Her books on writing include Starting Your Career as a Freelance Writer, The Writer’s Guide to Queries, Pitches and Proposals (Second Edition), and Writing to Win: The Colossal Guide to Writing Contests.