When there is a main event and events before it, we use the past perfect to describe the earlier events and the Past Simple to describe the main event.
Earlier events
- When she opened the door, he had already left.
- I realised that I had been there before.
- When I met her, I had never been in a serious relationship.
- He noticed I had cleaned the car.
How much or how many had been done
- We had driven 500 miles and we needed some rest.
- How many hours had he slept when you woke him up?
Stative verbs
We use past perfect with Stative or non-action verbs to describe events that had started earlier in the past with a “duration” (e.g., how long, for, since, always, etc)
- The day Anne died, they had been married for 48 years.
- The day I left, I had been in England for exactly 4 years.
- She told me she had always hated her sister.
References