Sentence Types

A sentence is a collection of words that forms a complete thought. It has two main parts:

• a subject – the noun (or pronoun) that the sentence is about
• a predicate – the verb (or verb phrase) that attributes action to the subject.

To develop a writing style that is engaging for a reader, try to incorporate a variety of sentence types into your work. Although there are many different structures and lengths that sentences can have, we can distinguish three main types of sentences:

• simple sentences
• compound sentences
• complex sentences

Despite the language of “simple” and “complex”, one type of sentence isn’t better than the other. Each sentence type has its own purpose depending on the thought or idea that you’re trying to express.

Simple Sentences

A simple sentence consists of just one independent clause (i.e., a complete thought that has a subject and a verb). For example:

Canada must address the climate change problem.

In the above sentence, “Canada” is the subject and “must address” is the verb phrase.

A simple sentence need not be a short sentence. We can build phrases around the core independent clause. For example:

According to Williamson (2013), Canada must address the climate change problem in the coming decades.

In the simple sentence above, we have two phrases built around the independent clause – an introductory phrase (i.e., “According to Williamson”) and a prepositional phrase (i.e., “in the coming decades”).

Compound Sentences

A compound sentence has two or more independent clauses, which are joined by a coordinating conjunction. You can remember the different coordinating conjunctions by the acronym “FANBOYS” – for, and, not, but, or, yet, so.

In this context, a coordinating conjunction connects independent clauses that are of equal importance. For example:

Canada must address the climate change problem, and it will require considerable changes to our way of life.

By using a coordinating conjunction to link two independent clauses, the writer is telling us that the two ideas are of equal importance.

Notice that we use a comma before the coordinating conjunction to separate the two independent clauses.

Complex Sentences

A complex sentence has one independent clause and one or more dependent clauses.
A dependent clause has a subject and a verb, but it does not express a complete idea. For example:

Although Canada must address climate change

A dependent clause is not a complete sentence. On its own, a dependent clause is a fragment. For this idea to become a complete sentence (and a complex sentence), we need to include an independent clause. Instead of linking these two clauses with a coordinating conjunction, complex sentences are formed with a subordinating conjunction such as:

• Although
• While
• Because
• Despite
• Even though
• After
• When

For example:

Although Canada must address climate change, it will require considerable changes to our way of life.

Unlike a compound sentence that treats the two clauses as having equal importance, a complex sentence prioritizes the importance of the independent clause over the dependent clause. In other words, the dependent clause is subordinate to the independent clause.

To Conclude

When composing a sentence, pay attention to what you are attempting to express to your reader. Are your ideas of equal importance or do you wish to subordinate one idea to the other? Consider the difference in meaning between the following sentences:

Two simple sentences: Many countries refuse to accept even a partial ban on whale hunting. Some species of whales are nearing extinction.

A compound sentence: Many countries refuse to accept even a partial ban on whale hunting, but some species of whales are nearing extinction.

A complex sentence: Because many countries refuse to accept even a partial ban on whale hunting, some species of whales are nearing extinction.

The two simple sentences do not express a relation between the two ideas. The compound sentence regards the two ideas as of equal importance. In this case, the coordinating conjunction “but” indicates contrast between the two ideas. The complex sentence, on the other hand, demonstrates a more specific connection between the two ideas. In this case, a causal connection has been articulated, one that puts the emphasis on “some species of whales are nearing extinction”.

By being intentional about what types of sentences to use to express your ideas, you can better ensure that you communicate your intended meaning to your reader.

Writing Services, Wilfrid Laurier University, CC By-NC 2023