Complex Sentence: What Is a Complex Sentence? Definition and Examples

Do you want to learn more about what a complex sentence is? This article will teach you what you need to know to understand and use them in your writing.

In short:

• A complex sentence consists of an independent clause and at least one dependent clause.

This guide is part of our free online Grammar Book.

What Is a Complex Sentence?

Sentences comprise a subject, a predicate, and at least one clause. The most basic of sentences has just one independent clause. The more complicated the sentence, the more clauses there are.

Complex sentences are one of four types of sentence structure.

The other three are:

• Simple sentences: just one independent clause.
• Compound sentences: two independent clauses.
• Compound-complex sentences: two (or more) independent clauses and at least one dependent clause.

A complex sentence has one independent clause and at least one dependent clause. 

They often use subordinating conjunctions to connect the clauses.

Independent and Dependent Clauses

Time for a quick grammar lesson (or review). Independent clauses can stand alone. They make sense on their own and constitute a complete sentence. On the other hand, dependent clauses don't convey a complete thought, so they can't stand alone.

Here's an example of an independent clause (also called a simple sentence):

I went to the store. 

Here's an example of a dependent clause:

When I finished work

As you can see, the dependent clause can't be used alone; it must be paired with an independent clause.

Let's try:

When I finished work, I went to the store. 

Now that's what I call a complex sentence! (Actually, that's what everyone calls a complex sentence).

Only complex and compound-complex sentences can have a dependent clause, making them great sentences to use when you want to provide more information. After all, you could say that you went to the store, but adding the dependent clause lets you explain that it happened after work.

Subordinating Conjunctions

I mentioned earlier that the independent and dependent clauses were often linked using a subordinating conjunction. But what exactly are they? Well, put simply, they are connecting words; that's pretty much their sole purpose, which explains why they are so great at joining clauses.

Here are some common ones:

• after
• before
• since
• while
• as
• until
• how
• though
• unless

Complex Sentence Examples

If you don't study harder, you'll fail your exams.

Can you let me know when you're done in the bathroom?

I'm not leaving here until you get out of bed and put on some clothes.

While you were getting a manicure I was over here dealing with this mess.

Though he knew he could never make the baseball team, he still dreamt of it. 

Concluding Thoughts on Complex Sentences

That concludes this article on complex sentences. I hope you found it helpful and now feel more confident using them on your own.

Let's summarize what we've learned:

• A sentence comprises a subject and a predicate.
• Complex sentences are one of four types of sentence structure.
• An independent clause and a dependent clause are combined to make up a complex sentence.
• Use subordinating conjunctions to join the two clauses together.

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