The English language is confusing – to say the least. Sentence structure is tough, and many people struggle to write a complete sentence. In English, we have four main types of sentences: simple, compound, complex, and compound-complex.
The Simple Sentence
The simple sentence is just that! It’s a single independent clause (labeled I), which means it can stand alone and contains a subject and a verb.
The dog chased the rabbit. (I)
The Compound Sentence
The compound sentence includes two independent clauses combined by a comma and a conjunction (labeled c) OR a semi-colon. Conjunction words include the words of the acronym FANBOYS: for, and, nor, but, or, yet, so. *It’s important to note that if a conjunction word isn’t used, a semi-colon must be used instead of a comma (or you’ll end up with the pesky comma splice!).
The dog chased the rabbit, but the rabbit got away. (I,cI)
The dog chased the rabbit; the rabbit got away. (I;I)
The Complex Sentence
The complex sentence has one independent clause and one or more dependent clauses. Unlike the independent clause, the dependent clause cannot stand alone (even though it still has its own subject and verb). Dependent clauses often begin with words such as even, because, although, if, or when. The tricky thing with the complex sentence is knowing when to use a comma. If the independent clause comes first, a comma is NOT used. If the dependent clause comes first, however, a comma IS needed.
The dog chased the rabbit because he wanted to catch it. (ID)
Because he wanted to catch it, the dog chased the rabbit. (D,I)
The Compound-Complex Sentence
The compound-complex sentence combines the compound and complex sentences together. It has two or more independent clauses and one or more dependent clauses. The use of the comma (or the lack thereof) follows the rules above.
The dog chased the rabbit because he wanted to catch it, but it got away. (ID,cI)
When in doubt, I always recommend sticking to simple sentences. Not only are you less likely to have errors, but studies show they’re also more easily understood and accurately comprehended by our readers. Sentences with eight or fewer words typically have a 100% comprehension rate. As the sentences get longer, that percentage drops drastically!