This week, we are starting a series of short posts to help students brush up on common grammar errors and how to avoid or correct them. Today we tackle two problems with that oft misunderstood element of punctuation–the comma.
Missing Comma after an Introductory Element
When you use an introductory word, phrase, or clause to begin your sentence, you should use a comma after it to indicate a short pause. You don’t always need a comma if the element is very short, but it’s never wrong to include it.
Missing Comma in a Compound Sentence
A compound sentence is one in which two or more sentences are joined by conjunctions (for, and, nor, but, or, yet, so). You always place a comma before the conjunction. However, you do not use a comma before the conjunction (and, but, or) when you have only a compound verb or subject.
One way to make sure you use correct punctuation for both of these situations is to cover up the conjunction with your finger. Now read what is on each side to see if it’s a complete sentence by itself (subject, verb, and a complete thought is expressed). If yes, use a comma; if not, then no comma is needed.
The Oxford Comma
The Oxford comma refers to the comma right before the conjunction in a series of three or more items. Depending on the style of writing, it may or may not be used. In many cases, though, as in the meme above, leaving it out can drastically change the intended meaning.
If you read the sentence above, it implies that the writer’s heroes are his or her parents who happen to also be Superman and Wonder Woman. If, however, you were to insert a comma before “and,” it then changes the meaning of the sentence. It’s then inferred that the writer’s heroes are his or her parents and Superman and Wonder Woman.
If there’s any chance that your readers will be confused about the meaning of your sentence, it’s better to use the Oxford comma rather than to leave it out.
