What Had Been Happening Before Something Occurred
Past Perfect Continuous
The past perfect continuous expresses the duration of an activity up to another point in time in the past. The use of the past perfect continuous stresses that a certain activity had been going on before something important happened.
Example:
How long had you been reviewing bed and breakfasts before you picked your favorite?
He hadn't been staying up late in conversation with the mice during the six weeks before he called pest control.
How long had the appetizers been laying on the plate before the party goers consumed them all?
Positive Form:
Subject + had + been + 'ing' form of verb + (object(s)) + time expression
He had been sticking to his special-diet for six months before his blood pressure fell.
Negative Form:
Subject + had + not + been + 'ing' form of verb + (object(s)) + time expression
The cereal hadn't been sitting in the bowl long before it grew soggy.
Question Form:
(Question Word) + had + subject + been + 'ing' form of verb?
How long had the appetizers been laying on the plate before the party goers consumed them all?
Past Perfect Contrasted with Past Perfect Continuous
The past perfect expresses something that finishes before another activity in the past. The past perfect continuous, on the other hand, expresses the duration of an activity at the moment something important happened in the past.
Past Perfect Examples:
The rooms manager hadn't had time to prepare before he made the presentation.
I had already visited three state parks by the time I began visiting the national parks.
Past Perfect Continuous Examples:
He had been sticking to his special-diet for six months before his blood pressure fell.
He hadn't been staying up late in conversation with the mice during the six weeks before he called pest control.