Different uses of the present perfect and the past perfect
We use the Present Perfect Simple for an action or a state that began in the past and is connected with the present i.e. The action still continuous now or there is a result in the present from the action.
• The house is dirty. They haven't cleaned it for weeks.
• We aren't hungry. We've just had lunch.
We use the Present Perfect Continuous to show an action or a state that started in the past and has continued up until now with duration.
We use the Past Perfect Simple to express a completed action in the past before another action in the past.
• The house was dirty. They hadn't cleaned it for weeks.
• We weren't hungry. We'd just had lunch.
We use the Past Perfect Continuous for emphasizes a duration of an action which happened before another in the past.
- The Past Perfect Continuous gives past activities time and duration.
- In the Present Perfect Continuous the action began in the past and continues to the present.