Past Perfect Continuous Tense

     PAST PERFECT CONTINUOUS TENSE

·         (+) S + had been + Verb Ing

Martha had been watching for 2 hours when I came at seven.

·         (-) S  +  had not been + Verb Ing

Martha had not been watching for 2 hours when I came at seven.

·          (?) had + S + been +Verb Ing ?

Had you been eating mango?

v  Question: The senior engineer (manage) the project for a year before he resigned.

v  Answer: The senior engineer had been managing the project for a year before he resigned.