Past Perfect Continuous Tense

Past Perfect Continuous Tense
Function: The past perfect continuous tense is used to talk about longer situations that continued up to the moment in the past we are talking about.
Example

In Active :        (+) S + had + been + Ving + object
                  She had been eating a chicken

                   (-) S + had + not + been + Ving + object 
                    She had not been eating a chicken

                  (?) Had + S + been + Ving + object
                   Had she been eating a chicken?