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:
They hadn't been using that credit card account long when they used up their card's limit.
She had been doing well financially until she wrote a bank draft for more than was in her account.
They had been explaining the fixed exchange rate when the officer entered the hall.
Positive Form:
Subject + had + been + 'ing' form of verb + (object(s)) + time expression
She had been doing well financially until she wrote a bank draft for more than was in her account.
Negative Form:
Subject + had + not + been + 'ing' form of verb + (object(s)) + time expression
They had not been discussing the negative points about capital allowance when the manager entered the office.
Question Form:
(Question Word) + had + subject + been + 'ing' form of verb?
How long is it going to take them to decide on the take over bid so we can start real work
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:
I had already agreed to the terms before they offered the additional collateral.
They hadn't come up with enough votes before they protested the bill.
Past Perfect Continuous Examples:
They hadn't been using that credit card account long when they used up their card's limit.
How often had you been checking your safety deposit box prior to the break-in?