While commas are typically used to indicate a natural pause when reading a sentence aloud, they do have other uses. Let’s look at a few of them today.
Commas are used to separate items in a list. For example, “Laura studied different types of animals, including mice, rats, rabbits, cats, and dogs. “ The last comma before the “and” in this sentence is called the Oxford comma. While this comma is optional in some formats, you should always be consistent throughout your paper whether you choose to use it or not.
Commas are also used to separate independent clauses (clauses that can stand by themselves) connected by “and,” “but,” “yet,” “so,” “nor,” “for,” and “or” (these are called coordinating conjunctions). An example of this is: “I have five friends, and I enjoy spending time with them.” If you are not certain if a comma is required, take a closer look at the sentence. Can the second portion (the part that follows the coordinating conjunction) stand alone and make sense? If so, you need to add a comma. If it cannot, then you do not need a comma.
You should be sure to include a comma after an introductory word or phrase (a dependent clause). An example of this is: “In the beginning, the plot of the book was slow and dragged on.” Some other introductory elements are: “in the end,” “however,” “while,” “after,” “unfortunately,” and “finally.”
Commas should be added when you incorporate a dependent clause in a sentence. The correct way to do this is: “Stephen’s bicycle, which he received as a birthday gift last year, was stolen from the bike rack.”
Commas should also be used when attributing quoted information, such as: “I need to go home,” said the traveler.
Be sure to add commas when stating full dates, for example: Monday, July 15, 2019.
If a sentence starts with a “yes” or “no” answer that can stand alone, you should include a comma, such as in the sentence: “Yes, I am leaving now.”
If you are directly addressing someone, you should include a comma after their name: “Rebecca, can you please pass that package to me?”
While there are times that you should use a comma, there are also times when you should not. One of the most common errors involving commas that this editor finds in papers is the comma splice.
Two independent clauses should not be held together by a comma. If you do this, you have created a comma splice, such as in the sentence: “We brought the computer to the store, it was fixed within an hour.” There are two ways to correct this problem. The first strategy is to replace the comma with a period: “We brought the computer to the store. It was fixed within an hour.” The second method is to add a semicolon: “We brought the computer to the store; it was fixed within an hour.”