The post Simple Comma Rules 1-2 is part of a series called Writing Tips. This series is devoted to helping you become a better and more effective writer. To see previous Writing Tips posts, click here.
Growing up, the only guideline for using commas that I remember receiving was vague: commas go where you would naturally pause when speaking. This guideline is relatively subjective, as where one person pauses, another may not. It’s perhaps more important to ask: why do we need pauses? Pauses in speech (or commas in writing) separate ideas or thoughts in order to avoid confusion. If you have to stare at a sentence and read it a few times before the meaning is clear, you have a confusing sentence. And you’re likely lacking commas.
From experience, I know that my tolerance for talking and reading grammar-related materials is much higher than most. To avoid having your eyes glaze over and your brains shut down, I’ve broken up the rules. Today I will discuss two rules, and I’ll discuss two more rules in a couple of weeks.
To clarify information in lists
Rule #1: Use commas to separate items in lists.
When making a list of three or more items, place a comma after each item on the list. And yes, I highly recommend using the serial comma. This is the best way to keep confusion to an absolute minimum. Lists can be lists of nouns, lists of verbs, lists of prepositional phrases–just about anything. (Forgot the parts of speech?)
The ball is purple orange and blue.
Is the ball purple-orange and blue, or three different colors? To best separate all items, you need commas!
–> The ball is purple, orange, and blue.
List items can be more than one word, however.
For our date, we can have dinner at a restaurant on Thursday go to a movie on Friday or visit a winery on the weekend.
Can you see the list items?
For our date, we can [have dinner at a restaurant on Thursday] [go to a movie on Friday] or [visit a winery on the weekend].
As with our one word list items, we also add a comma at the end of each item to separate them.
–> For our date, we can have dinner at a restaurant on Thursday, go to a movie on Friday, or visit a winery on the weekend.
To separate clauses in complex sentences
Rule #2: Use a comma in complex sentences when the dependent clause comes first.
Did your mind just shut down a bit? Complex sentences? Dependent clauses? Do not walk away quite yet! I can make this relatively simple for you. Clauses are complete thoughts–they have a subject and verb–and clauses can be separated into independent and dependent clauses. Dependent clauses depend on an independent clause for meaning. The example I always give my students when I explain the difference between independent and dependent clauses is quite simple. I tell them to imagine me running into the classroom and yelling something at them.
“Because I like pizza!”
“When we see each other again!”
If whatever I said does not make sense without more information, it is a dependent clause. Its meaning depends on the independent clause–something that, in my examples, is lacking.
If you’re worried about being able to identify dependent clauses, you can use clues to help you. There are conjunctions (subordinate conjunctions) that signal the presence of a dependent clause: because, when, since, although, though, and others.
So, where do commas come in? Both of the examples I listed above have the dependent clause coming second. Complex sentences are flexible in that it usually does not matter which clause comes first. If the dependent clause comes first, however, it must be followed by a comma:
[Because I like pizza], I want pizza tonight for dinner.
[When we see each other again], we’ll talk.
Because the English language is recursive (meaning you can put clauses within clauses within clauses), you should also be aware that complex sentences can be composed of more than one independent and one dependent clause. (<– Look! A complex sentence with the dependent clause first.) Take care, however, because the more complex sentences get, the more difficult they are to understand—even with commas. Which is why, if you read academic studies, you will find that they take much longer to read and comprehend than other materials.