A compound sentence allows us to share a lot of information by combining two or more related thoughts into one sentence. It combines two independent clauses by using a conjunction like “and.” This creates sentences that are more useful than writing many sentences with separate thoughts.
Compound sentences are important because they allow us to shorten the things we say or write. They express our thoughts in a way that allows our audience to receive information easily and quickly. Often, everything we want to say can be summarized, and it is generally the best choice for communicating. So remember: more words don’t necessarily mean more information.
2. Examples of Compound Sentences
We use compound sentences all of the time. Here are some examples, the independent clause is green, the second is purple, and the conjunctions are orange:
Let’s take a look at the following section to find out what is an independent clause and a conjunction.
3. Parts of Compound Sentences
A compound sentence has at least two independent clauses and always includes a conjunction.
a. Independent Clause
An independent clause has a subject and a predicate and makes sense on its own as a complete sentence. Here are a few:
The parrot ate popcorn.
The wolf ran quickly.
He ate candy apples.
He went to the mall.
So, you can see that all of the clauses above are working sentences. All sentences have an independent clause, but all compound sentences have at least two independent clauses.
A conjunction is a word in a sentence that connects other words, phrases and clauses. The most common conjunction that you know is “and.” Other common conjunctions are for, but, or, yet, and so. A compound sentence needs at least one conjunction to connect two or more complete sentences.
Conjunctions are important because they let us combine information, but still keep ideas separate so that they are easy to understand. A compound sentence without a conjunction would be a run-on sentence, and would sound very confusing! Here are two sentences, with and without conjunctions:
The boy ran to the park then he ate a hotdog.
The boy ran to the park, andthen he ate a hotdog.
So, you can see that we need a conjunction to for the sentence to be clear!
It is important to know that the word “then” is NOT a conjunction—it’s an adverb. So, when you are writing a compound sentence and want to use “then”, you still need a conjunction, for example, “so then,” “but then,” or “and then.”
As mentioned, a compound sentence combines two independent clauses. Some common formats for compound sentences are:
one subject performing two different actions
two completely different subjects doing performing actions
a. When one subject does more than one thing:
The boy ran to the park.
The boy ate a hotdog there.
These sentences have the same subject, “boy,” but two verbs, “ran” and “ate.” Since both sentences are about what the boy does at the park, we can combine them:
The boy ran to the park, andhe ate a hotdog there.
This compound sentence is the best way to share the information from the two original sentences. Even though the boy does two different things, we can explain them in one sentence because they are related to each other.
Remember not to confuse this with a compound predicate. We can also say:
The boy ran to the park and ate a hotdog there.
In this example, we don’t mention the boy twice, so we don’t have two separate sentences. Ate ahotdog is only a verb phrase, so we don’t need a comma.
Let’s try another example, again starting with two sentences.
Compound sentences are a great tool in writing, and come naturally in speaking. As mentioned, they exist to help you unite multiple related ideas into one strong sentence. For example, here are three simple sentences:
The cheetah ran fast.
She ran all the way to the movies.
There, she ate a hot pretzel.
We really don’t need three separate sentences to share this information, because it’s all about the same subject. So, let’s combine all three of the sentences above to make one compound sentence:
The cheetah ran fast; she ran all the way to the movies, and there she ate a hot pretzel.
The compound sentence still has the subject “cheetah,” but it now shares both of the things she did at the county fair, “ran” and “ate.”
Finally, it’s important to remember that compound sentences combine related information. Even if you follow the proper grammar pattern, it doesn’t mean you can combine any old thing with another. You don’t want to make the mistake of putting things together that have nothing to do with each other, like this:
Mary went to the market yesterday and she gardens every morning.
In this sentence, the first point is that Mary went to the market yesterday, and the second is that she gardens every morning. But, these things are not related to each other, even though they are both about Mary. It seems like they came from two different stories. So, while there is nothing wrong with the grammar, this is not a proper compound sentence because the ideas are unrelated.