not sure what the difference between a simple subject, simple predicate, complete subject and a complete predicate are

Answer 1

The simple subject is a noun or pronoun. The simple predicate is the verb.

Example:
Katy is working.
Katy is the simple subject.
is working is the simple predicate.

The complete subject is the simple subject and its modifiers. The complete predicate is the verb plus other words that go with it.

The man in the blue car almost ran a red light.

Complete subject:
The man in the blue car
Complete predicate:
almost ran a red light.

http://www.chompchomp.com/terms/subject.htm

http://grammar.about.com/od/grammarfaq/a/What-Is-A-Predicate.htm