Simple sentence

A simple sentence (sometimes called an independent clause) is a sentence that contains a subject and a predicate (a verb). It also must express a complete thought. This follows the rules of syntax in English grammar.
Length.
A simple sentence is not defined by how short it is. A simple sentences is often short and uncomplicated. But it is not limited by the number of words used to express the thought. For example:
Simple or dependent?
A simple sentence or independent clause is one that has a meaning to a reader or listener. If the sentence does not complete the thought, it may be a dependent clause. A dependent clause is one that does not express a complete thought. By itself it is a sentence fragment. It may look like a simple sentence, but it will not make sense on its own.