Compound Sentences

Compound sentences can make writing rich and colorful. While beginning writers generally learn to write simple sentences first, compound sentences provide more detail and make paragraphs more interesting and engaging. When forming compound sentences, it is important to understand the components of a compound sentence and to use the proper punctuation to join clauses.

What is a Compound Sentence

A compound sentence contains two or more independent clauses joined by a coordinator.  It is distinct from a complex sentence, which is an independent clause that is joined with a dependent clause.

What is an Independent Clause

In independent clause is a clause that contains 3 things:

1. A subject (something or someone that the sentence is about)
2. An action (a verb- something that is being done)
3. A complete thought (there are no questions as to meaning at the end of the sentence)

What is a Coordinator

There are 7 coordinators in the English Language:

1. For
2. And
3. Nor
4. But
5. Or
6. Yet

You can use the acronym FANBOY to help you remember the 7 coordinators in the English language.

When you have 2 independent clauses joined by one of these coordinators, that is a complex sentence. Usually a comma is required, before the coordinator.

Examples of Complex Sentences

• Alex likes to fish, and he is going fishing on Friday. Alex likes to fish is an independent clause. "Alex" is the subject, "likes" is the action, and a complete thought is expressed.
• He is going fishing on Friday is an independent clause. "He" is the subject, "is going" is the action, and a complete thought is expressed.
• The coordinator "and" is used, and a comma is correctly used before the "and."

• Becky wishes she could be younger, for everyone else in the program is half her age. Becky wishes she could be younger is an independent clause. "Becky" is the subject, "wishes" is the action, and a complete thought is expressed.
• Everyone else in the program is half her age is an independent clause. "Everyone else in the program" is the subject, "is" is the action, and a complete thought is expressed.
• "For" is the coordinator, and a comma is correctly used before the "for."

• She is going to the store, or she is going to the mall.

• She is going to the store is an independent clause. "She" is the subject. "Is going" is the action, and a complete thought is expressed.
• She is going to the mall is an independent clause. "She" is the subject. "is going" is the action, and a complete thought is expressed.
• "Or" is the coordinator, and a comma is correctly used before the "or."

• I am very smart, yet I do not enjoy school. I am very smart is an independent clause. "I" is the subject, "am" is the action, and a complete thought is expressed.
• I do not enjoy school is an independent clause. "I" is the subject. "enjoy" is the action. A complete thought is expressed.
• The coordinator "yet" is used, and correctly preceeded by a comma.

Sentences That Are Not Compound Sentences

Only independent clauses joined by one of the above coordinators are compound sentences. When an independent clause and a dependent clause are joined, a complex sentence is formed, which is distinct from a compound sentence.

• When I visit my mother, I eat cookies.

• This is NOT a compound sentence because "When I visit my mother" is not an independent clause and a coordinator is not used. 

• I like to fish because fishing is fun.

• Although "I like to fish" is an independent clause and "fishing is fun" is an independent clause, this is still not a compound sentence. It is a complex sentence, since none of the seven coordinators are used here.