Complex Sentences

Complex sentences are considerably different from simple and compound sentences because they contain clauses which are not equal to the main clause.

These unequal clauses are known as subordinate or dependent clauses. The subordinate clause is not a complete sentence and therefore cannot stand on its own.

The subordinate clause is often called the dependent clause because it relies on the main clause to make sense as a statement.

This type of sentence is most useful when you want to include ideas that are more important than others, and if you wish to be more precise with your sentences.


Perhaps the best way to demonstrate the differences between complex, compound and simple sentences is to use an example.

Please note the differences in the following 3 examples:

Simple: We ate the apples. They were delicious.

Compound: We ate the apples and they were delicious.

Complex: We ate the apples because they were delicious.

With the simple example we can see that there are two independent sentences. Both stand alone as individual and complete sentences.

In the compound example note that the two complete sentences are simply joined together by a coordinating conjunction, the word 'and.' Yet they could still stand alone as independent and complete sentences. This would be the case even if we were to remove the 'and.'

Most interestingly in the third example - the complex example - something entirely different has occurred. The addition of the link word 'because' has created a subordinate clause. The clause '...because they were delicious,' cannot stand alone as a complete thought, hence it is dependent on the main clause, 'We ate the apples.'

Additionally, the added conjunction 'because' tells us why we ate the apples. It presents the information, contained in the sentence, with more precision.

Complex Sentence Guide
Right-click to download this PDF file here.


Andrews, R. Torgerson, C. Beverton, S. Freeman, A., Locke, T., Law, G., (2006) The effect of grammar teaching on writing development. British Educational Research Journal, 32, 39-55

Merrick, D. (2009) Blake's Grammar Guide for Primary Students. Pascal Press

Content Last Modified 8/11

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