Simple sentence: a group of words containing one subject/predicate combination; an independent clause (can stand alone)
Example: My mom bought a dress.
Compound sentence: joins two simple sentences or two independent clauses
Example: My mom bought a dress, but I thought it looked silly.
There are two ways to properly make compound sentences:1. A comma and a COORDINATING CONJUNCTION (FANBOYS)
For, And, Nor, But, Or, Yet, So
I like pizza, but Sue prefers pasta.2. A semi-colon
I like pizza; Sue prefers pasta.
Go here to practice: