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:
We hadn't been assessing the data for long when they demanded a firm percentile.
We'd been working on the peace-building process for five months when the ambassador rejected the plan's premise.
How long had you been working on forming an advocacy alliance before the other nonprofit backed out?
Positive Form:
Subject + had + been + 'ing' form of verb + (object(s)) + time expression
The Senate Ad Hoc Committee had been debating the bill for three hours when they called for a vote.
Negative Form:
Subject + had + not + been + 'ing' form of verb + (object(s)) + time expression
We hadn't been assessing the data for long when they demanded a firm percentile.
Question Form:
(Question Word) + had + subject + been + 'ing' form of verb?
How long had you been interviewing for the new personnel positions before the company's bankruptcy became public?
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:
She hadn't had time to request oversight before she made the announced cutbacks.
We hadn't had time to prepare an action alert before the street protests erupted spontaneously.
Past Perfect Continuous Examples:
We hadn't been assessing the data for long when they demanded a firm percentile.
The Senate Ad Hoc Committee had been debating the bill for three hours when they called for a vote.