what is sometimes called a simple preicate?

Answer 1

you mean simple predicate?

Answer 2

The predicate is the verb part of a sentence. A simple predicate is just the verb. For example, in the sentence:
Mary ran.
Mary is the subject, ran is the predicate, and it is a simple predicate.

However, in the sentence:
Mary ran headlong into the enormous fence.
Mary is the subject, "ran headlong into the enormous fence" is the predicate, but it's not a simple predicate.

Answer 3

if you mean simple predicate, it is the verb.