Commas in Compound Sentences
Essential Question
How do commas help us join complete ideas that work best together?
Grammar in the World
What Do I Know?
What do you already know about using commas to join two independent clauses together? Use this interactive to find out.
Building Blocks
Grammar is a complex system and structure of language. Mizzou Academy Grammar Lab spotlights one skill (or block) at a time, but it’s often helpful to see how a skill works together with other, related blocks to build the language structure as a whole. You may find the following resource topics helpful as context for this lesson:
Learn About Commas in Compound Sentences
When we create compound sentences, we can use coordinating conjunctions (for, and, nor, but, or, yet, so) to put two independent clauses together.
An independent clause has a subject and a verb. There are a variety of ways to put independent clauses together to create compound sentences, but when you use a coordinating conjunction, you need a comma to go with it. The comma is what identifies where the first complete idea ends in a compound sentence and where the next complete idea begins.
|
Independent Clause #1 |
Comma + Conjunction |
Independent Clause #2 |
Compound Sentence |
|
I went to the store |
, and |
I bought a cake |
I went to the store, and I bought a cake. |
|
I went to the store |
, but |
I did not buy a cake |
I went to the store, but I did not buy a cake. |
|
I can go to the store |
, or |
I can buy a cake |
I can go to the store, or I can buy a cake |
Here is a summary list to help you remember how to create compound sentences with a comma.
- You must have two independent clauses.
- You must separate the two independent clauses using a comma + a coordinating conjunction.
- Coordinating conjunctions can be remembered using the acronym FANBOYS.
|
In a compound sentence, always place a comma before the coordinating conjunction. (To help remember which conjunctions are coordinating conjunctions, remember the acronym: FANBOYS.) |
|
|
For |
Baseball teams can charge television stations a lot of money to air their games, for the sport is so popular it’s known as “America’s Pastime.” |
|
And |
The game begins when the first batter comes to the plate, and the pitcher throws the first pitch. |
|
Nor |
A pitcher cannot intentionally hit a batter with a pitch, nor can he use any substances to improve the speed or aim of his throws. |
|
But |
A team’s manager can ask umpires to review a play on the field, but he cannot argue balls and strikes. |
|
Or |
A runner might be called out if a fielder catches the ball before it hits the ground, or he might be tagged out before he reaches the next base. |
|
Yet |
A runner should be called out if the catcher tags him at home plate, yet he will be safe if the catcher drops the ball. |
|
So |
There are a lot of different offensive and defensive plays that happen in any given inning of a baseball game, so many fans fill out score cards to help keep track of it all. |
|
Common Errors |
|
|
Only use a comma with a coordinating conjunction that connects independent clauses. These are complete thoughts that each contains its own subject and its own verb. Do not use a comma with a coordinating conjunction that joins compound subjects or compound verbs. |
Both the pitcher, and the catcher are defensive positions. Both the pitcher and the catcher are defensive positions. The catcher is a defensive position, and the pitcher is a defensive position, as well. The designated hitter bats last in the line-up, and usually hits the most home runs. The designated hitter bats last in the line-up and usually hits the most home runs. The designated hitter bats last in the line-up, and he usually hits the most home runs. |
|
Do not place a comma after a coordinating conjunction. The comma should appear at the end of the first complete thought. |
The baseball championship is called The World Series but, it’s not really a global event. The baseball championship is called The World Series, but it’s not really a global event. |
Do I Get It?
Check your understanding of how to punctuate compound sentences with this interactive exercise.
Read each of the following sentences and consider the comma placement. Decide where the punctuation is incorrect or correct.