Although ordinary conversation, personal letters and even some types of professional writing (such as newspaper articles) consist almost entirely of simple sentences, effective writers know how to use all types of sentences in their texts. Writers who employ only simple sentences are like truck drivers who do not know how to shift out of first gear: they would be able to drive a load from Montréal to Calgary, but they would have a great deal of trouble getting there.
If you use phrases and clauses carefully, your sentences will become much more interesting and your ideas much clearer. For example, the following complex sentence develops a major, central idea and provides structured background information:
Just as a good driver uses different gears, a good writer uses different types of sentences in different situations: