building blocksComplex Sentences

In previous lessons, we learned about simple and compound sentences. A third type often used by good writers of English is the complex sentence. A complex sentence consists of at least one independent clause (simple sentence) and one or more dependent clauses. Look at these examples of the three different types of sentences.

Look at these examples of the three different types of sentences.

Two simple sentences

Jason’s father likes cars.
He works in a garage.

Compound sentence

Jason's father likes cars, and he works in a garage.

Complex sentence

Jason’s father, who works in a garage, likes cars.

In the last example “who works in a garage” is a dependent clause. It has a subject (who) and a verb (works), but alone it makes no sense. Only when we join it to an independent clause (simple sentence) can we understand the meaning. Here are some other dependent clauses.

Example Explanation
when it rains subordinator = when, subject = it, verb = rains
after we eat subordinator = after, subject = we, verb = eat
as soon as they arrive subordinator = as soon as, subject = they, verb = arrive
because it was late subordinator = because, subject = it, verb = was
if the weather is nice on the weekend subordinator = if, subject = weather, verb = is

These dependent clauses begin with subordinators. Words such as when, after, before, as soon as and while are subordinators of time. Because and since are subordinators of reason and if is a subordinator of condition. The word subordinate means less important, so subordinators tell readers that the clauses they introduce are not the most important parts of the sentence. See how they make sense when they are connected to independent clauses.

Be careful. Coordinating conjunctions show that the things being joined are equal. For example, they can be used to join two subjects, two verbs or two phrases. It’s only when they join two or more independent clauses (simple sentences) that they create compound sentences. Let’s look at some examples.


When it rains, the roads are slippery. / The roads are slippery when it rains.

After we eat, let’s go shopping. / Let’s go shopping after we eat.

As soon as they arrive, we’ll eat. / We’ll eat as soon as they arrive.

Because it was late, we went home. / We went home because it was late.

If the weather is nice on the weekend, we’re going camping. / We’re going camping if the weather is nice on the weekend.

Warning: Don’t confuse because, which is an adverb clause subordinator, with because of, which introduces a noun. Study the following examples. The first is a complex sentence with the reason subordinator because. The second is not.

Because we were hungry, we stopped to eat dinner.

Because of hunger, we stopped to eat dinner.


Good writers vary their work by using different sentence structures. If you combine complex sentences with simple and compound sentences, your writing will also be much more interesting.

When you are sure that you understand the lesson, you can continue with the exercises.