The Past Perfect Continuous Tense

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.

Past Perfect Continuous Timeline

For example:

"By the time I left England we had been living in Bristol for five years."

"His back was sore because he had been sitting at the computer all day."

It is also used to say how long something went on for up to a past time.

For example:-

We apologised because we had kept them waiting for 3 hours.

We apologised because we had kept them waiting since lunchtime.

!Note It is always for a length of time and since a point in time.