Question

Identify the simple predicate in the following sentence.

Answer 1

"Has been waiting" should be your answer. a simple predicate is the verb or verb phrase in the sentence and it usually tells what the subject does. 

Answer 2

Answer: The simple predicate in the sentence provided is "has been waiting".

Explanation: The simple predicate of a sentence is the main verb or verb phrase, which indicates what the subject is, does or feels. The modifiers of the verb are not part of the simple predicate, only the verb/verb phrase is. In the sentence provided, the main verb phrase is "has been waiting". Moreover,  it indicates what the subject ("My mother") has been doing; therefore, "has been waiting" is the simple predicate in that sentence.