Main Principle: Past Perfect has three conditions:
1. Action was in the past
2. Action was completed (i.e. finished)
3. Action took (or, to put it more precisely: had taken) place before a particular point (moment) in time in the past
Signal words for point in time in Past Perfect:
After
before
by
by the time
Point in time in Past Perfect:
another action (usually in Past Simple)
I had done my lessons before my brother came.
After I had done my lessons, my brother came.
time on clock
I had done my lessons by 3 pm.
event
I had done my lessons before the exam.
date
I had done my lessons by the 1st of October.
contextual time (not explicitly indicated, however, we can understand it from context)
Contextual time: Past Perfect
Contextual time can be any time point (another action, time on clock, event, date) that we can infer from the situation (context).
(question) How did you pass the exam?
(answer) I had done my lessons. (point in time is not explicitly indicated)
Here, contextual time is “before the exam.” It falls into event category. Just to make sure we are using Past Perfect correctly, we can convert this sentence:
I had done my lessons before the exam.
As you can see, the above example circles back to the previous one.
Simple way to explain Past Perfect
Well, another way to explain Past Perfect, not that scientific, however, closer to our human nature, is:
When something happened before something else. The one, happened earlier, is in Past Perfect.
In conclusion
But do we always follow this rule of “action before something in the past”? Can’t we just use Past Simple all over? Well, the world will not crash if we do. However, if we use beautifully constructed sentences, that convey what we truly want to say, isn’t that wonderful? Keep learning!
When we have a sequence of actions, to show how a story was unfolding, we don’t have to use the Past Perfect. We only use it to stress on the fact that an action was already complete before a point in time.