Compound Sentence

compound sentence

Remember that an independent clause (unlike a dependent clause) can stand alone as a sentence. Knowing the difference between independent and dependent clauses is essential for understanding sentence structures.

Examples of Compound Sentences

Jack likes Jill , but Jill likes Mark .
I can smell lemons , but she can smell oranges .
Autumn is ending , and winter is coming .
He was a loyal cabin boy , and he knows where the treasure is buried .

What Does "Compound" Mean?

A compound is something composed of two or more separate elements.

In chemistry, iron is an element, sulphur is an element, but iron sulphide is a compound. In English, a compound sentence has two independent clauses. Similarly, a compound adjective is an adjective with two or more parts (e.g., free-range eggs, never-to-be-forgotten experience), and ice-cream is an example of a compound noun.

Real-Life Examples of Compound Sentences

Only two things are infinite, the universe and human stupidity , and I'm not sure about the former . (Physicist Albert Einstein)
There used to be a real me , but I had it surgically removed . (Actor Peter Sellers)
Go , and never darken my towels again . (Comedian Groucho Marx) (Note: Go is the shortest sentence in English.)
Any fool can criticize, condemn, and complain - and most fools do . (Author Dale Carnegie)

Joining the Independent Clauses in a Compound Sentence

In a compound sentence, the independent clauses are joined using one of the following 5 methods:

(1) a conjunction with a comma (e.g., ", and")

I like tea , and he likes coffee .

I like hot chocolate ; it sends me to sleep .

I know one thing : I love that girl . (This is rare because the words after a colon are not often an independent clause.)

I know you're here — I can smell your perfume .

(5) a conjunction with a semicolon (e.g., "; and")

After the lights went out, I could hear you whispering ; and I know you were talking about me . (This is rare because it's an outdated style.)

The Four Types of Sentence Structure

A compound sentence is one of four main sentence structures, all of which are shown below. In these examples, the independent clauses are shaded.

A Complex Sentence

Diplomacy is the art of saying "nice doggie" until you can find a rock. (Actor Will Rogers)

A Compound Sentence

Some men are born mediocre , some men achieve mediocrity , and some men have mediocrity thrust upon them . (Author Joseph Heller) (This example has three independent clauses.)

A Simple Sentence

A country can be judged by the quality of its proverbs . (German Proverb)

A Compound-Complex Sentence

I stopped believing in Santa Claus when he asked for my autograph in a department store, but I still want to believe in him .

Why Compound Sentences Are Important

There are two great reasons to learn about compound sentences.

(Reason 1) Deciding whether to put a comma before "and" (or any conjunction).

A conjunction (e.g., "and," "or," "but") that joins two independent clauses in a compound sentence is preceded by a comma. A conjunction that joins two of anything else is not normally preceded with a comma. For example:

She tells great jokes and sings brilliantly. (There is no comma before "and." This is a simple sentence. It is just a list of two verbs, "tells" and "sings.")
She tells great jokes, and she sings brilliantly. (This time, there is a comma before "and." This is a compound sentence. The clauses either side of the "and" could be standalone sentences, i.e., they're independent clauses.)

Here is a real-life example. In this example, the independent clauses are shaded.

A geek is a guy who has everything going for him , but he's just too young . He's got the software , but he doesn't have the hardware yet . (Filmmaker John Hughes) (Note that the conjunctions (in bold) are preceded by commas because the clauses either side of them are independent clauses. This is two compound sentences.)
A geek is a guy who has everything going for him but is just too young . He's got the software but doesn't have the hardware yet . (Note the commas have gone. This is two simple sentences.)

The trick is to look for a subject-verb pairing after the conjunction. If both are present in both halves of your sentence, then you should put a comma before your conjunction. Read more about commas with conjunctions.

(Reason 2) Avoid the run-on sentence.

You cannot join two independent clauses with just a comma. That causes a mistake known as the run-on sentence.

Dogs have masters , cats have servants .
Cannibals don't eat clowns , they taste funny .
I didn't fall , I'm just spending some quality time with the floor .

Let's fix them.

Dogs have masters , but cats have servants .
Cannibals don't eat clowns ; they taste funny .
I didn't fall — I'm just spending some quality time with the floor .

Video Lesson

Here is a 6-minute video explaining "compound sentence": video lesson

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This page was written by Craig Shrives.