Why use complex sentences?

In English, we have three types of sentences: simple, compound and complex. Each is better in particular situations.

Complex sentences join an independent clause with a dependent clause. These sentences are used to show a particular kind of relationship—usually a stronger idea joined to a weaker idea, or a controlling idea joined to a secondary, less important idea. Yet sometimes the independent clause is the weaker or less weighty idea compared to the dependent clause.

girl writing and thinking

Why are complex sentences used?

  • Complex sentences show relationships between clauses, such as cause and effect, contrast, and time relationships. For example, I took a walk because I need exercise.  Or, although my brother likes peaches, my sister prefers blueberries.  Or, Daniel headed home as soon as the movie ended.
  • Complex sentences can mimic the complicated thinking required to understand certain kinds of ideas, such as logic. Or, they can replicate the patterns of thinking of a deep thinker.  For example, if A is less than B, and if B is less than C, then A is less than C.  Or, the detective figured out that Morgan was the murderer because Morgan had a motive, even though his girlfriend, Emma, provided an alibi.
  • Complex sentences can force the reader to focus on one part of a sentence (one idea) rather than another part of a sentence.  For example, the Supreme Court–especially Justice Scalia–disdains creating law by its decisions since enacting laws is the job of Congress.
  • Complex sentences can gather small choppy sentences into more graceful, longer sentences.  For example, Dad grilled the chicken.  Mom mixed the salad.  The children set up a croquet game.  Later they would play.  First they would eat.  Joined together these tiny sentences become While Dad grilled the hotdogs and Mom mixed the salad, the children set up a croquet game which they would play after they ate.
  • Complex sentences can form the skeleton of informal, cumulative sentences which are patterned on the way people speak. For example, Jack said, “I expect a storm because the clouds are building up, which is a sure sign a thunderstorm is coming on hot, humid Atlanta summer afternoons like this one.”

Complex sentences can begin with the independent clause or the dependent clause; the choice belongs to the writer. Most children start with the independent clause, adding the dependent clause as they think through their ideas. Usually children limit themselves to only a few types of dependent clauses: adverbial clauses beginning with “because,” “after” and “when.” Almost never do they use relative pronouns to create complex sentences.

How can you encourage children to use complex sentences with more variety?

  • For younger children, I prepare worksheets with lists of two sentences needing to be combined. I suggest the word that needs to link the sentences, and they must write the new sentence.
  • For older children, I write a list of subordinate conjunctions from which they can choose in order to join sentences in a list which I provide. I might stipulate that half the sentences need to begin with the subordinate conjunction to force them to start sentences with the dependent clause.
  • When I am working with a group of children, I have a “spelling” bee, asking students to create a complex sentence using a particular subordinate conjunction.

Once children learn to use complex sentences, they need to be warned about overusing them. Too many complex sentences can make writing difficult to follow. So can the number of dependent clauses. Even though the number of dependent clauses which can be attached to an independent clause is unlimited, using more than two usually muddles meaning. Encourage students to limit dependent clauses to one or two per sentence, and to mix up complex, compound and simple sentences for variety.

I have been told that some languages do not contain complex sentences, that in those languages, if ideas are joined, it is by words like “and” and “but.” In those languages it is normal to show equality of ideas but not inequality. Just like having many English verb tenses makes English a richer yet more difficult language, so does having complex sentences.

What's your thinking on this topic?