Commas can be a real pain in the…grammar behind for many writers. It starts in elementary school and continues on through life with only the Grammar Nazis ever fully grasping their meaning, purpose, and how to use them. Well, the truth is that commas are not near as hard as the teachers have made them out to be nor what our minds tell us. But all those years of being told how hard it was to use commas has done its damage, especially when it comes to conjunctions.
Maybe we can shed a little light on the subject matter.
What is a Conjunction?
Let’s start off with knowing what a conjunction actually is. A conjunction is a word that connects two complete sentences together. The typical conjunctions most people are familiar with are ‘and’, ‘but’, and ‘or’. These are the ones you’ll see most often connecting two sentences. It will connect sentences like:
He ran across the yard.
John pulled on the door.
These are two independent sentences that can stand on their own. Yet, they can be part of the same scenario. When that is the case, you can use a conjunction to pull them together and paint them happening at the same time in your brain.
He ran across the yard, and John pulled on the door.
The one person ran across the yard while John pulled the door open. You can see the action taking place in a fluid motion. Also, if you put the sentences side by side in a paragraph, they almost sound too juvenile. Combining them with a conjunction helps them mature a little bit. This is a great way to create a more dynamic piece of writing.
Now the comma part of all this…
And the Comma...
As these are two separate sentences that can stand alone, you need a comma to tell you that. What is the purpose of a comma? It is a reading directional. As you are reading, it tells you where to pause and where deviations occur. Here, it is telling you this is not a single sentence by itself. It is two separate sentences combined for better reading. It is a slight way to show you how the sentence is really being acted out.
The conjunctions used depend on what you are trying to say with the combined sentence. ‘And’ means in addition to. He ran while John was pulling. Both are happening which means ‘and’ is the better fit. What if I used ‘but’? That would convey something entirely different.
He ran across the yard, but John pulled on the door.
This conveys a hint that they could have done the same thing. Maybe something is after them, and one guy decides to make a run for it while the other one attempts to get inside a house. Instead of working together, they appear to make different decisions which is important to the story. That one little word can change the entire meaning of the sentence.
The comma is placed before the conjunction to let you know that you need to pause. When you do, you take notice of the conjunction. You notice whether it is an ‘and’ or a ‘but’. Your mind then processes that and interprets the scene based on that and the context it is found it. The picture in your mind adapts to the comma and conjunction.
When Not to Use Comma
Now that we have seen how to use the comma with a conjunction, let's look at not using it. Sounds odd, but you'll understand in a minute.
John bought a truck and called Susie up on the way home.
The conjunction here should not have a comma. Look at "called Susie up on the way home." This is a sentence fragment when you put it by itself. It cannot stand on its own. Therefore, it does not need anything more than a conjunction as it has to have the first part of the sentence to be a solid sentence. Don't put a comma in front of the conjunction in this case.
If you ever have a question about a conjunction and if a period is needed, there are many resources online to help you. You can do a search on how to use commas. You'll find resources such as Purdue Owl, which a final authority for many learning institutions, and Grammar Girl.
S Maree on September 07, 2017:
Love it! I truly wish we had instruction like this when I learned grammar. "School House Rock" came when I was a teen and WAY too cool to watch Saturday morning TV. Even though I earned a BA in English, I hated grammar!
Thank you for the resources. I'm getting rusty in the art of punctuation and need refreshers. Had a professor who was enamored of James Joyce, and insisted we learn to make entire (long!) paragraphs using but one sentence. Crikey! Should have paid better attention because now I'm embarrassed how much I need to edit even short responses as this.
Please feel free to send more such missives! Thank you and have a lovely day!