Simple, Compound, Complex, and Compound-Complex Sentence Structures

There are four types of sentence structures, which represent different combinations of independent and dependent clauses. 

An Independent Clause has a subject and verb and makes a complete thought.

• I ate breakfast.
• I went to school.

A Dependent Clause has a subject and verb, but does not make a complete thought. It does not make sense by itself. It must have more information to form a complete thought.

• Before I went to school.
• After I ate breakfast.

Simple Sentence = 1 Independent Clause 

A simple sentence has at least one subject and one verb. It makes one complete thought. It is an independent clause. A simple sentence can have a compound subject or a compound verb or both.

 1. Simple Sentence = Subject + Verb + Complete Thought

• We eat watermelon in the summer. 
• My name is Bob.
• What is your name?

3. Compound Verb = Subject + More than one Verb

• I washed and dried my hair.
• We hiked and canoed on vacation. 
• Did you eat or drink anything?

Compound Sentence = 2 Independent Clauses

A compound sentence has two independent clauses joined together. There are two ways to join a compound sentence.

1. Independent Clause + Comma + Coordinating Conjunction + Independent Clause

• I like art class, and I like music class.
• I have a cat, but I don't have a dog.

Coordinating Conjunctions: for, and, nor, but, or, yet, so (FANBOYS)

2. Independent Clause + Semicolon + Independent Clause 

Complex Sentence = Independent + Dependent Clause

A complex sentence has one independent and one dependent clause combined with a subordinate conjunction. There are two ways to form a complex sentence depending on which clause is first.

1. Independent Clause + Subordinate Conjunction + Dependent Clause

• She made a call before she visited her friend.
• Independent Clause: She made a call
• Dependent Clause: before she visited her friend.

2. Subordinate Conjunction +  Dependent Clause + Comma + Independent Clause

• Before she visited her friend, she made a call.
• Independent Clause: she made a call
• Dependent Clause: Before she visited her friend.

Subordinating Conjunctions always introduce dependent clauses: after, as if, before, as long as, as soon as, because, during, even though, if, since, though unless, until, when, whenever, where, wherever, while,

Compound-Complex Sentence = 2 Independent Clauses + 1 or more Dependent Clause/s

A compound-complex sentence has two independent clauses and one or more dependent clause/s. How can one identify a compound-complex sentence? Look for three subject + verb clauses and two conjunctions.

• Sentence: We go to the lake in summer, but my dog stays at home because he gets carsick when travelling. 
• Independent Clause: We go to the lake in summer
• Independent Clause: but my dog stays at home.
• Dependent Clause: because he gets carsick when travelling.

• Although he had a lot of work to do, he took a break, and he returned feeling refreshed and ready to work again.

• Independent Clause: he took a break.
• Independent Clause: and he returned feeling refreshed and ready to work again.
• Dependent Clause: Although he had a lot of work to do.