17.2: Sentence Structures- Simple, Compound, Complex, and Compound-Complex

There are four specific sentence structures to consider as you draft, revise, and proofread your work: simple, compound, complex, and compound-complex. Each of these structures relates to the others, but each also creates a unique understanding of the content of a sentence; by choosing a different sentence structure, you can demonstrate the connection between related ideas, highlight contrasting thoughts, punctuate a particularly salient point, or direct your readers’ attention to multiple areas of thought at once.

Beginning with the most basic structure, the aptly-named “simple” sentence, you can see how the different structures build upon one another, combining different elements to shift your readers’ perspective.

See this page for a simple overview of the sentence types.

The Simple Sentence

Do not let its name fool you: a simple sentence may be basic in its structure, but the ideas it expresses can be as complicated (or straightforward) as you wish. By “simple,” we just mean that the sentence contains the minimum elements required for a complete sentence (subject, verb, and object or complement).

Example: My writing has improved since high school.

Example: I used to write sentence of about the same length.

Example: They all sounded pretty much the same.

The Compound Sentence

Also aptly named, the compound sentence combines two independent clauses to connect complete, related ideas

Example: My writing has improved since high school, and now I can construct an essay without mechanical errors.

Example: I used to write sentences of about the same length, but these days their lengths ebb and flow with my thoughts like the tides.

Example: They all sounded pretty much the same, so they just came across as dull and even lifeless.

How to create a compound sentence:

1. Join the independent clauses with a comma and a coordinating conjunction (for/and/nor/but/or/yet/so)
2. Connect two independent clauses with just a semicolon
3. Use a semicolon followed by a transition that is NOT a coordinating conjunction (however, for example, as a result) and a comma to join two independent clauses.

The Complex Sentence

This structure begins to deviate from the standard formula, as it introduces the dependent clause into the mix. A complex sentence, then, combines an independent clause (a group of words that can stand alone as a sentence) with a dependent clause (a group of words that adds meaning but cannot stand alone as a sentence) through a tool called subordination. Compare the following sentences to the example sentences you saw in the discussion of compound sentence:

Example: Because my writing has improved since high school, I can now construct an essay without mechanical errors.

Example: Whereas I used to write sentences of about the same length, these days their lengths ebb and flow with my thoughts like the tides.

Example: Since they all sounded pretty much the same, they just came across as dull and even lifeless.

Subordination sets up a dependent relationship within a sentence, and there are several key terms that you can use to establish this relationship. While not exhaustive, the following chart includes a selection of common subordinating terms that you can use to set up a dependent relationship within your sentences. For additional information on subordination, see Chapter 5.

Common Subordinating Terms

After, although, as, as long as, because, before, besides, even if/even though, if/if only, in order to, now that, once, rather than, since, though, without, unless, until, when/whenever, where/whereas/wherever, whether, while, within

The Compound-Complex Sentence

As its name suggests, this final structure combines compound and complex sentence forms, resulting in a sentence that contains at least two independent clauses and one dependent clause. As before, compare these sentences to those you saw as examples given in the earlier discussions of simple sentences and compound sentences.

Example: While I used to dread writing papers for English classes, my writing has improved since high school, and I can now construct an essay without mechanical errors.

Example: When I was a younger, more-timid writer, I used to write sentences of about the same length, but these days their lengths ebb and flow with my thoughts like the tides.

Example: Since they all sounded the same, even I dreaded reading my own writing, for they just came across as dull and even lifeless.

See this page from the Writing Center at UNC Chapel Hill on the sentence structures for further examples and explanation.