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.

Structure #1: Simple Sentences

A simple sentence is one independent clause. A clause is a group of words that contain a subject and a verb, and an independent clause it a group of words that form a complete thought when you put them together. Here are some examples:

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

Again, all of these sentences are complete thoughts.

Structure #2: Compound Sentences

A compound sentence is made of two independent clauses joined by a coordinating conjunction .

Although the most commonly used coordinating conjunctions are but, and, so, and or, there are seven coordinating conjunctions in English:

• F = for
• A = and
• N = nor
• B = but
• O = or
• Y = yet
• S = so

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

Structure #3: Complex Sentences

A complex sentence has a dependent clause and an independent clause. The dependent clause can come at the beginning of the sentence or at the end. Here are some examples:

• She fell asleep because she was tired .
• Because she was tired , she fell asleep.
• I'll call you if I go .
• If I go , I'll call you.

(Note: When a dependent clause starts a sentence, you should put a comma at its end to show where the clause ends.)

An adjective clause (also known as a relative clause) is also considered a dependent clause as well. E.g.:

• This is the store where I bought my hat.
• Vancouver, which is in western Canada , is a beautiful city.

Structure #4: Compound-Complex

A compound-complex sentence has the following:

1. two independent clauses joined a coordinating conjunction
2. a dependent clause

The dependent clause can be anywhere in the sentence. Here are some examples:

• She took out her umbrella because it was raining , and then she walked home.
• I don't like exercising, but I'll do it if I have to .
• The man who was on the other side of the street waved, so I looked at him.

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, w riting 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. I n 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).
  • 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.
  • 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.
  • I n short, writing effectively and efficiently means using a variety of sentence structures.

  Do you think you understand? Try our exercises below!

  Exercises #1: Identifying Sentence Structures

  1. The man smiled and laughed.
  2. The man smiled, but I did not know why.
  3. When the cat is away, the mice will play.
  4. The answer is not known.
  5. If people would like to apply, they can call 1-800-493-222 or they can e-mail inquiries@abccompany.com .
  6. He asked me a question so I answered.
  7. I e-mailed the company, and they responded immediately, which surprised me.
  1. Simple (Independent clause) Note: "and laughed" is not a clause because it does not contain another subject and verb. Therefore, this sentence only has one clause
  2. Compound (Independent clause + coordinating conjunction + Independent clause)
  3. Complex (Dependent clause + Independent clause)
  4. Simple (Independent clause)
  5. Compound-complex (Dependent clause, independent clause + coordinating conjunction + independent clause)
  6. Compound (Independent clause + coordinating conjunction + Independent clause)
  7. Compound-complex (Independent clause, coordinating conjunction, independent clause, dependent clause)

  Exercises #2: Identifying Sentence Structures

  1. The train station was still closed but a few coffee shops were open.
  2. If you have further questions, please do not hesitate to ask.
  3. Some people only need a computer to do their jobs, so they can easily work from home.
  4. On the second weekend of July last year, I went camping.
  5. As population increases, food shortages become more common and quality of life can decrease.
  6. The price of the service increased by 20%, but because the company did not inform its customers, many people demanded an explanation.
  7. Many students didn't understand, so their teacher explained the answer very clearly and slowly.
  1. Compound (Independent clause + coordinating conjunction + Independent clause)
  2. Complex (Dependent clause + Independent clause)
  3. Compound (Independent clause + coordinating conjunction + Independent clause)
  4. Simple (Independent clause) Note: "On the second weekend of July last year" is a prepositional phrase, not a clause because there is no subject or verb.
  5. Compound-Complex (Dependent clause, Independent clause + coordinating conjunction Independent clause)
  6. Compound-Complex (Independent clause, coordinating conjunction, dependent clause, independent clause)
  7. Compound (Independent clause, coordinating conjunction, Independent clause)

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

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