Core Grammar #3: Types of Sentence Structure

The 4 Types of Sentence Structure

In What is a sentence? we saw the minimum requirements for the formation of a sentence. Now we can look in more detail at the four types of sentence structure.

The 4 Types of Sentence

Simple Sentence Structure

A simple sentence consists of one independent clause. (An independent clause contains a subject and verb and is structurally complete.)

independent clause

Compound Sentence Structure

A compound sentence is two (or more) independent clauses joined by a conjunction or semi-colon. Each of these clauses could form a sentence alone.

independent clausecoordinating conjunctionindependent clause

There are seven coordinating conjunctions:

Another way to join two independent clauses in a compound sentence uses a semicolon.

independent clausecoordinating conjunctionindependent clause

Complex Sentence Structure

A complex sentence consists of an independent clause plus a dependent clause. (A dependent clause starts with a subordinating conjunction or a relative pronoun, and contains a subject and verb, but is not structurally complete.)

independent clausedependent clause

Here are some common subordinating conjunctions:

Here are the five basic relative pronouns:

Compound-Complex Sentence Structure

A compound-complex sentence consists of at least two independent clauses and one or more dependent clauses.

independent clausedependent clausecoordinating conjunctionindependent clause

A dependent clause is also called a subordinate clause.

The above sentences are basic examples only. In some cases other arrangements are possible (for example, a dependent clause can come before an independent clause).

A type that doesn't work

Comma Splice Structure

A comma splice is a type of run-on sentence which imitates the structure of a compound sentence, but lacks the necessary pieces (usually the coordinating conjunction).

independent clausecoordinating conjunctionindependent clause

This error is a favorite of many students, and you will also see it in loosely-edited professional writing.¹ Because a comma splice is a grammar error and because it leads to a very boring writing style, most careful readers (professors and potential employers) see it as evidence of sloppy writing and poor education.²

  1. This sentence wasn't a run-on because it had the coordinating conjunction and after the comma.
  2. This sentence wasn't a run-on because it began with a subordinate clause which started with the subordinating conjunction because. (Actually, there were two of them.)

This page was adapted from:

"The 4 Types of Sentence Structure" EnglishClub: Learn or Teach English, 2018, Accessed 16 May 2018.

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The contents of this page have not been reviewed or approved by Ashland University.
Revised 5/23/18 • Page author: Curtis Allen • e-mail: