Simple, Compound, Complex Sentences | Learning English

What is Sentence Structure?

Sentence structure is how the basic grammatical elements (a subject, predicate, and sometimes direct or indirect objects) of a sentence are put together. The rules for how a sentence is constructed are simple but firm. These include the necessity for a subject, predicate, and object (in that order) in every sentence. Beyond that, we can add additional elements like prepositions and dependent clauses. Advanced sentences can weave these elements together to create more and more complex structures. There are four types of sentence structure (listed below).

Types of Sentence Structure:

  • Simple
  • Compound
  • Complex
  • Compound-complex

Simple Sentences

The most basic type of English sentence is the simple structure. This is when a sentence is composed of just one independent clause – a clause which contains a subject (the noun performing the action of the sentence) and predicate (the action being taken) and expresses a complete thought. Like all sentences, it can also contain a direct object (the noun receiving the action of a sentence) or indirect object (the object for whom the action is being done). 

A few simple sentence examples:

  • I didn’t go to the game.
  • She was correct.
  • The writer was out of ideas.
  • The movie was over two hours long.

Compound Sentences

The compound sentence combines two or more independent clauses with a coordinating conjunction (or, and, but, yet, for, nor, so) or a semicolon.

Here are some examples:

  • She was sick, so she didn’t go to school.
  • Greg kept his distance; he knew he was a dangerous man.
  • I was exhausted, but I worked all night.
  • Mom was still at work, and Dad was out to dinner.


Notice how all of these sentences could be broken into two: “She was sick. She didn’t go to school.” “Mom was still at work. Dad was out to dinner.” That’s because these sentences contain 2 independent clauses, which can be turned into simple sentences.

Complex Sentences

Complex sentences consist of an independent clause and a dependent clause. A dependent clause is an incomplete thought (e.g., “Although I was sick, ...” “Because he was gone, ...”) and thus needs to be attached to an independent clause. It’s also known as a subordinate clause.

Some complex structure examples:

  • If he was so funny, the whole crowd would have been laughing.
  • I went to dinner because I was hungry.
  • She turned her down because she was in love with someone else.

Compound-Complex Sentences

True to their name, compound-complex sentences combine the ideas behind both compound and complex sentences: they contain at least two independent clauses and a dependent clause. 

Because they can be pretty hard to parse, I’ve color coded the independent clauses, the coordinating conjunction/semicolon, and the dependent clauses. Let’s take a look:

  • Because he was injured, the team played with a short bench and their rivals beat them soundly.
  • I wondered what became of him; if he liked Chicago so much, it made no sense for him to up and leave.
  • The teacher gave Jimmy a time-out because of his bad behavior and we all laughed at him, reveling in the chaos he had wrought.