A compound sentence combines two simple sentences. We need a comma after the first simple sentence in the compound sentence. Look at this example: The rain is falling, and the wind is blowing.
Notice that there are two separate sentences in this compound sentence:
The rain is falling. The wind is blowing.
When we push them together into one sentence, we put a comma after the first sentence and add the word and before the second sentence.
As writers, we get so used to seeing ,and that we assume that every and needs a comma. However, that’s not true. Look at this sentence:
Bill drove to work and parked the car.
We have two actions here – drove to work and parked the car. It might seem like we need a comma in here, but we don’t. Take out and. Try to make two simple sentences. Bill drove to work. Parked the car.
Do you see how these are not both sentences? Only the first one is a sentence because Bill is doing something. The second one is not a sentence because it has no subject – no person doing something.
What’s the lesson here? That we need to be sure there are two simple sentences joined into one compound sentence before we use a comma with and.
Here are more sentences. Look at which ones use a comma and which ones don’t. Can you tell the difference?
Mom is working from home today, and Dad wants to go shopping.
Dad has to drive to the train station and park the car.
He often rides the train, and I like to go with him.
Only use a comma with and if you have a complete sentence on both sides of the and.
▶It’s your turn. Only one of these two sentences needs a comma with and. Can you figure out which sentence is written correctly? Jack mowed the lawn, and pulled the weeds. Jack mowed the lawn, and Sarah pulled the weeds. Did you choose the sentence with two separate simple sentences as the correct sentence? Good for you!