1. SIMPLE SENTENCE
Contains one independent clause (a noun + a verb) and no dependent clauses.
Form:
Subject + Predicate
Ex. George is fast.
COMPOUND SENTENCE
Contains two independent clauses.
Forms:
Independent Clause + ; + Independent Clause
Ex. George can run 60 miles per hour; I think he is very fast.
Independent Clause + Coordinating Conjunction + Independent Clause
Ex. George can run 60 miles per hour, so I think he is very fast.
Independent Clause + ; + Conjunctive Adverb (transition word) + , + Independent
Clause
Ex. George can run 60 miles per hour; therefore, I think he is very fast.

2. COMPLEX SENTENCES
Contains an independent clause and at least one dependent clause.
Forms:
Independent Clause + (no punctuation) + subordinate clause
Ex: George can run 60 miles an hour because he is very fast.
Subordinate Clause + , + Independent Clause
Ex: Because he is very fast, George can run 60 miles per hour.