Compound Sentence: A compound sentence is one that has two or more independent clauses linked by a coordinator (which, for, as, and, or, ...)
Complex Sentence: A complex sentence is one that has an independent clause and one or more dependent clauses.
Complex-Compound Sentence: A compound-complex sentence is composed of two or more independent clauses and one or more dependent clauses.
Simple Sentence: A simple sentence consists only of an independent clause.
An independent clause is one that makes sense alone in a sentence, on the other hand, a dependent clause does not make sense on its own and needs another sentence to make sense.
