1) When we give an account of a sequence of past events we usually put these events in chronological order using the past simple. If we want to refer to an event out of order – an event which happened before the last event in the sequence we have spoken about – we use the past perfect.
a) He was a wealthy landowner who emigrated to Mexico in 1959. The agricultural reforms had begun a few month before this. He moved again in 1965 and made his home in the United states. He had made his fortune in growing sugar cane as a young man in Cuba.
2) When we understand that we are talking about events before another past event, we don’t have to continue using the past perfect.
a) We bought a new car last month. We had driven my parents’ car for ages, but it started to fall apart. We put a new engine in it, but that didn’t solve the problem.
3) We can use either the past perfect or past simple when we talk about things that we intended to do but didn’t or won’t now do in the future.
a) I had hoped to visit the gallery before I left Paris, but it’s closed on Sundays.
4) If we talk about how many times something happened in a period up to a particular past time, we use the past perfect.
a) I had stayed in the hotel twice since the 1980s
b) How many times had you met him before yesterday?
c) We had visited Edinburgh a few times before.