Complex Sentences

Many people have trouble putting the wonderful and complicated ideas they’ve developed onto paper. When they read what they’ve written they wonder why the ideas don’t “flow” or why the sentences don’t seem to express the full complexity of the ideas.

One way to fix this lack of flow is to diversify sentence structure. Most students will be familiar with the simple sentence. (Eg: Margot loves doing dissections!) This sentence has a noun (Margot) and a verb (loves) and expresses a complete thought. This is also called an independent clause.

Another kind of sentence is the compound sentence. (Eg: Margot loves doing dissections, and she gets to do one this week.) This sentence has two parts which are of equal weight and are joined by a coordinator (for, and, nor, but, or, yet, so). This type of sentence joins two ideas by using a conjunction, but both ideas could have been expressed independently and still have the message conveyed properly.

The complex sentence is a real gem of the English language. This type of sentence’s true value is its ability to express intricate concepts by establishing dependent relationships between ideas. Sounds hard, eh? It’s truly not. Complex sentences are just the next logical step after compound sentences.

A compound sentence puts two independent clauses together with a joining word. A complex sentence, on the other hand, uses something called a dependent clause. A dependent clause is similar to an independent clause but it cannot stand alone as a sentence. In practical terms, this means that one part of the sentence (the dependent clause) relies on another part of the sentence (the independent clause) for complete meaning.

For example:
Although Hamlet appeared insane, his soliloquies provide evidence to the contrary.
When Columbus voyaged across the Atlantic, many people thought him to be mad.
The king of France declared war even though his advisors were against it.

In each of these examples, it is possible to determine relationships between ideas. Complex sentences can show time, cause/effect and contrasting associations. In the first example, we are contrasting Hamlet’s apparently insane behaviour with the heartfelt introspection when he his alone. Using a complex sentence in this way directly links the two ideas and helps increase the “flow” of the writing.

Dependent clauses in complex sentences are often used as adverbial modifiers – meaning they modify or restrict the meaning of a sentence. In this case, they require commas. For more information about comma use, check out the blog “Commas”.



The chart above provides some key words and phrases that are helpful if you wish to add complex sentences to your work. An essay with a variable sentence structure is easier to read, and using complex sentences provides a writer with the tools to express intricate thoughts.


References: (MLA style)

Aaron, Jane E. & Murray McArthur. The Little, Brown Compact Handbook, 2nd ed. Toronto: Pearson Education Canada, 2003.

Hacker, Diana. A Canadian Writer’s Reference, 2nd ed. Scarborough: Nelson Thomson Learning, 2001.

Kris