Four Sentence Structures: Simple, Compound, Complex, & Compound-Complex

There are four sentence structures in English: Simple, Compound, Complex, and Compound-Complex. Here are examples of each:

1. She ate lunch.  (Simple: one independent clause)
2. She ate lunch, but she was still hungry. (Compound: two independent clauses joined by a coordinating conjunction).
3. She was still hungry even though she had eaten lunch. (Complex: an independent clause + a dependent clause)
4. She was tired, and she was still hungry even though she had eaten lunch (Compound-Complex: two independent clauses joined by a coordinating conjunction and one dependent clause)

First: Understanding Clauses

A clause is a group of words that includes a subject and a verb. It's important to understand that there are two types of clauses:

Independent Clauses

A sentence must have at least one independent clause. An independent clause is a group of words that form a complete thought when you put them together. Here are some examples:

• She ate lunch. 
• The car drove on the road. 
• On Tuesday, I had my test. 

These sentences are complete thoughts, which means that no more information is needed to understand them completely.

Dependent Clauses (Subordinate Clauses)

Dependent clauses are incomplete thoughts. They depend on an independent clause in order for the sentence to have meaning. Dependent clauses begin with a subordinate conjunction. Here are some examples:

• when I got home (what happened?)
• because the restaurant was closed (what happened because it was closed?)
• whom I respect very much (whom are we talking about?)

As you can see, more information is needed. To create a complete sentence, you need to add an independent clause. Here are the examples again but written as complete sentences (known as complex sentences):

• I washed the dishes when I got home.
• We couldn't eat because the restaurant was closed.
• The company's owner is Alice Brown, whom I respect very much.

Now that you understand this, we can look at the four different sentence structures.

The above sentences are all independent clauses joined by a coordinating conjunction, so they are all compound sentences.

Question: What about Compound-Compound? Complex-Complex?

Technically, you can make more complicated types of of sentence structures, for example:

• She arrived and then he arrived and then I arrived so we were all there.

Is this Compound-Compound-Compound sentence? No. It's still just called a Compound sentence. Also, it's a badly written sentence.

• Before she went home, she cleaned up the area where she had worked.

Is this a Complex-Complex sentence? No. It's still called a complex sentence, even though there are two dependent clauses.

Why is all this important? What sentence structures should I use?

Spoken English tends to mainly use simple and compound sentences, but higher-level writing (e.g. academic and business communications) should use some complex structures. A complex sentence can be more efficient because it can contain several ideas in the same sentence. Also, using conjunctions such although or because helps the reader understand how ideas relate to each other, which makes your writing more cohesive. 

Still, writing well doesn't mean only using long and complicated sentences. Writing is most effective when it's clear. This can be achieved by using short, simple sentences, such as this one. In short, writing effectively and efficiently means using a variety of sentence structures.

^ By the way, the above two paragraphs contained the following:

• Compound sentences: 1
  • Spoken English tends to mainly use simple and compound sentences, but higher-level writing (e.g. academic and business communications) should use a variety of structures (i.e. simple, compound, and complex).
• Complex sentences: 3
  • A complex sentence can be more efficient because it can contain several ideas in the same sentence.
  • Also, using conjunctions such 'although' or 'because' helps the reader understand how ideas relate to each other, which makes your writing more cohesive.
  • Writing is most effective when it's clear.
• Simple sentences: 3
  • Still, writing well doesn't mean only using long and complicated sentences. 
  • This can be achieved by using short, simple sentences, such as this one.
  • In short, writing effectively and efficiently means using a variety of sentence structures.
• Compound-complex: 0

Do you think you understand? Try our exercises below!

Exercises #1: Identifying Sentence Structures

Exercises #2: Identifying Sentence Structures

If you have any questions about sentence structures, please leave a comment below or visit our forums.

-- Created by Matthew Barton of Englishcurrent.com (Copyright)