Complete predicates are all words other than the subject and its modifiers. Simple predicates are only the verb with helping word (
i.e. has, have, had, was, is, etc.) If there are any.
Simple predicates are the part of the predicate that includes only the verb(s).
The dog stole and buried the bones.
"stole" and "buried" are the simple predicates.
They can actually be considered a compound predicate, which is a type of simple predicate in which the subject does two or more actions.
"stole and buried the bones" is the complex predicate. It includes everything that can modify the action.