Complex Sentences

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A complex sentence is a sentence that contains an independent clause and one or more dependent clauses. In this lesson, we will learn all about this type!

intermediate advanced

"Complex Sentences" in the English Grammar

What Are Complex Sentences?

A complex sentence is a sentence that has an independent clause and one or more dependent clauses.

Dependent vs. Independent Clauses

Independent clauses can be a sentence on their own, but dependent clauses cannot stand alone, even though they have a subject and a verb.

when I arrived at the airport → dependent clause

I was a happy kid → independent clause

How to Identify a Complex Sentence?

To identify a complex sentence you can look for subordinating conjunctions which are used to connect dependent and independent clauses.

Subordinating Conjunctions

Subordinating conjunctions are words that are used to link an independent clause to a dependent clause. The most common subordinating conjunctions are:

although
because
before
even though
if
since
until
when

Even though he is 31, he still acts like a little child.

Michael studied law because he wanted to become a lawyer.

Conditional Sentences

One of the most common types of complex sentences are conditional sentences. These sentences talk about hypothetical situations, often using 'if' or 'unless' as condition markers.

If you want to be a successful businessman, you have to understand the language of trade.

The baby won't go to sleep unless I tell him a bedtime story.

a complex sentence with coordinating conjunctions

Compound Sentence vs. Complex Sentence

Complex sentences are similar to compound sentences, with only one difference: compound sentences have two independent clauses, but complex sentences have one independent and one or more dependent clauses.

Joining Clauses Together

When an independent and a dependent clause join together to form a complex sentence, the sentence can have two structures:

the independent clause comes first:

I was snippy with him because I was running late for work.

the dependent clause comes first:

Because I was running late for work, I was snippy with him.

Punctuation

If the dependent clause comes first, it's best to separate the clauses with a comma. However, if the independent clause comes first, there is no need for a comma.

Review

'Complex sentences' are used with subordinating conjunctions. They are made up of one independent clause and one or more dependant clauses. The only difference between compound and complex clauses is that compound clauses are made up of two independent clauses.

Here are some examples of complex sentences.

Although I am not good at it, I enjoyed playing basketball with John.

Since she left me, I decided to raise our child on my own.