Simple sentence - is one independent clause — a group of words that has a subject and a verb and can stand by itself as a complete thought. (Example: The dog chased the ball.) A simple sentence may have a compound subject or a compound verb or both. Compound sentence - consists of two or more independent clauses linked by a word such as and, if, but, so, or or. (Example: Mr. Roberts was a teacher, but he also coached soccer.)

Complex sentence - contains one independent clause and one or more dependent or subordinate clauses—a group of words that has a subject and a verb but is not a complete thought. (Example: Although he was a science teacher, Mr. Roberts also taught math.)

Compound-complex sentence - contains two or more independent clauses and at least one dependent clause. (Example: Although he was a science teacher, Mr. Roberts also taught math and he was the dean of students.)