Perhaps because it is one of the most common punctuation marks, the comma is also one of the most commonly misused. Unnecessary commas abound, but this guide will help you steer clear of most common comma mistakes.
Knowing when to use commas includes knowing when not to use them. Unnecessary commas are a common grammatical error and occur in a variety of sentence constructions. For instance, a comma should never separate a subject from its verb. Unnecessary commas do this all the time:
By the same token, a comma should not separate a verb from its direct object:
In this case, “what the alarm meant” is the direct object of the verb “knew,” so it should not be separated from its verb by a comma.
With these quick and easy tips, you’ll be a pro at sidestepping common comma mistakes, from avoiding comma splices to connecting independent clauses to communicating your meaning clearly.
A comma splice is a type of run-on sentence. A run-on occurs when two clauses that can stand alone as sentences are presented as a single sentence. A comma splice is a run-on that occurs when two independent clauses are connected by a comma without an appropriate conjunction. “The man ate the pie, he didn’t pay the bill” is a comma splice. “The man ate the pie” and “He didn’t pay the bill” are independent clauses. The sentence can be fixed in three different ways.
You can separate the two clauses into independent sentences:
You can use a semicolon to properly connect the two clauses:
Or you can add a conjunction:
“Is there always a comma before ‘but’?” is a common comma question, and a good understanding of coordinating conjunctions will provide the answer. In one of the examples above, “but” was used as a conjunction to correct a comma splice. One of the most common comma mistakes is not using a comma before a coordinating conjunction (such as “but”) when the conjunction connects two independent clauses:
If you’re wondering whether there is always a comma before “but,” remember that the comma is only correct if the two clauses are both capable of standing alone as independent sentences. If the sentence has only one subject but has two verbs or objects, you shouldn’t use a comma:
The phrase “too sweet” is not a complete sentence, so you don’t use a comma before “but.”
“Because” is a conjunction that connects a dependent clause to its main clause. You do use a comma before “because” if the dependent clause that comes after it is merely supplementary—or parenthetical—information. Usually, you don’t need the comma at all:
In this example, a comma is not needed because the meaning of the sentence is clear. But sometimes, meaning can depend entirely on the presence or absence of a comma. In this example, the clause following “because” could give the sentence two meanings:
Did he not ask her out due to her pretty appearance, or did he actually ask her out for a different reason? The sentence is unclear. If you do use the comma before “because,” the second part of the sentence becomes an extra bit of explanation of the man’s actions:
Here, the sentence implies that perhaps this man is intimidated by attractive women, so he doesn’t like to ask them out.
In the example above, If you don’t use a comma before “because,” your sentence could mean the man asked the woman out for reasons other than her prettiness. You may need to add more information to make the situation clear:
He didn’t ask her out because she was pretty; he was attracted to her quick wit.
Whether you put a comma before “please” or a comma after “please” depends on the tone you want to strike and on the position of the word “please” in the sentence.
Let’s talk about tone first. For example, you could say this:
That’s perfectly acceptable. But you could also use a comma after “please”:
By adding the comma after “please,” the sentence changes tone, and the “please” sounds more irritated and exasperated. Both sentences are correct, but their tones are very different.
It’s generally fine to use a comma before “please” when it comes at the end of a sentence. But watch out! If you see a comma before “please” in the middle of a sentence, you may have run into one of those dreaded comma splices:
In this case, you must remove the comma before “please” and fix the comma splice:
“Not only” and “but also” are what are known as correlative conjunctions (much like “either/or” and “neither/nor”). Correlative conjunctions connect two parallel clauses or words. The “not only but also comma” issue is one that comes up a lot, but the quick and dirty rule to remember is that parallel verb or noun elements do not require commas:
When faced with the “not only but also comma” issue, remember that in most cases, you won’t need that unnecessary comma!
With these common comma mistakes out of the way, your writing will be better than ever. Join us for future articles on grammatical issues, or check out our list of 10 common writing errors and how to correct them. Or check out our description of different editing styles to gain insight into how your editors think.
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One thought on “Unnecessary Commas and Common Comma Mistakes”
Thanks so much for this post. I’ve always struggled with using too many unnecessary commas. I really like to sprinkle them everywhere! And I definitely didn’t know the rule about whether there is always a comma before “but”. Thanks for the examples. They make the rules a lot easier. Awesome article!