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.

Simple Sentence Structure

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

• I like coffee.
• Mary likes tea.
• The earth goes around the sun.
• Mary did not go to the party.

Compound Sentence Structure

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

• I like coffee, and Mary likes tea.
• Mary went to work, but John went to the party.

There are seven coordinating conjunctions:

• and, but, or, nor, for, yet, so
• These normally take a comma before the conjunction (but in very short sentences it sometimes gets omitted).

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

• Our car broke down; we came last.

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.)

• We missed our plane because we were late.
• Our dog barks when she hears a noise.
• He left in a hurry after he got a phone call.
• Do you know the man who is talking to Mary?

Here are some common subordinating conjunctions:

• after, although, as, because, before, how, if, once, since, than, that, though, till, until, when, where, whether, while

Here are the five basic relative pronouns:

• that, which, who, whom, whose

Compound-Complex Sentence Structure

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

• John didn’t come because he was ill, so Mary was not happy.
• He left in a hurry after he got a phone call, but he came back five minutes later.

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).

• John and Mary are in love, they plan on getting married.
• Ashland University is a small college in Ohio, it is a great place to live and study.

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, https://www.englishclub.com/grammar/sentence/sentence-structure.htm. Accessed 16 May 2018.

The views and opinions expressed in this page are strictly those of the page author.

The contents of this page have not been reviewed or approved by Ashland University.

Revised 7/17/22 • Page author: Curtis Allen • e-mail: callen@ashland.edu.