Complex Sentence

complex sentence

An independent clause (unlike a dependent clause) can stand alone as a sentence.

Examples of Complex Sentences

Subordinating Conjunctions in Complex Sentences

subordinating conjunction in a complex sentence

The word used to link an independent clause to a dependent clause is called a subordinating conjunction. The most common subordinating conjunctions are although, because, before, even though, if, since, until, and when. In these examples of complex sentences, the subordinating conjunctions are shown in bold.

The role of a subordinating conjunction and the dependent clause is to establish a time, a place, a reason, a condition, a concession, or a comparison for the main clause. (NB: Dependent clauses are also known as a subordinate clauses.) Read more about subordinating conjunctions.

The Four Types of Sentence Structure

A complex sentence is one of four main sentence structures, all of which are shown below. In these examples, the independent clauses are shaded.

A Complex Sentence

A Compound Sentence

A Simple Sentence

A Compound-Complex Sentence

Why Complex Sentences Are Important

There are two noteworthy issues related to complex sentences.

(Issue 1) Use a comma after a fronted adverbial.

Learning how to spot a complex sentence is useful because it helps with punctuating sentences correctly. In particular, it helps with deciding whether to use a comma with the dependent clause.

(Issue 2) Uh oh, there's more to Issue 1.

Unfortunately, there is a little more to Issue 1 than stated. The comma really determines whether the clause is restrictive or non-restrictive. However, the simple rule given at Issue 1 will satisfy 99% of situations. Read more about using commas with independent and dependent clauses (see Points 3 and 4).
Read more about adverbial phrases and adverbial clauses.

Learning the other sentence structures will also help with punctuating sentences correctly.

Video Lesson

Here is a short video explaining what we mean by complex sentence. video lesson

Are you a visual learner? Do you prefer video to text? Here is a list of all our grammar videos.

This page was written by Craig Shrives.