The past perfect is formed using the past simple form of the auxiliary HAVE and the past participle (third form) of the verb concerned:
I had worked….. we had played….. they had been …..etc
The past perfect is used for a number of purposes:
1. Earlier Past:
We use the past perfect to talk about a situation in a past time before one we are already talking about:
I finally got to the airport, but my plane had already taken off. [eg. The plane took off at 11.30; I arrived at 11.45]
The earlier situation can continue up to the later time:
I was sad to leave Durham when I graduated. I had spent three happy years there. [eg. I spent three years, 1994-1997, at Durham. I graduated in 1997]
We do not need to use the past perfect if we are simply describing a number of past situations, one or more of which happened after the other(s):
I visited my daughter in Manchester last March, and she came to see me at Christmas.
I spent three happy years in Durham, and then left to begin a new life in London.
1a. Past Perfect or Past Simple after Conjunctions?
When we are talking about an earlier past and use conjunctions such as after, before, as soon as, etc we can use the past perfect; however, it is usually not necessary if the sequence of events is clear:
After Paul moved out/had moved out, I decided not to look for a new flat-mate.
With when, there is a difference in meaning between the past and the past perfect:
When my father arrived, John left. [John left at the same time as, or very soon after, my father arrived.]
When my father arrived, John had left. [John left before my father arrived.]
2. Past Perfect or Past Simple in Indirect Speech
In indirect speech, the present perfect of the direct speech is usually changed to the past perfect:
“I have finished the report.” – Luke said that he had finished the report.
This is possible, but not essential, if the reported situation is still true at the moment of reporting:
– Luke said that he has finished the report. He is taking it to John now.
The past simple can be changed to the past perfect, but it does not have to be if the times of the situations are clear:
“George enjoyed his time with us over Christmas.” They said that George enjoyed/had enjoyed his time with them over Christmas.
3. Counterfactual Conditions
We use the Past Perfect when we talk about a past hypothetical situation that did not occur:
I wish I had passed my driving test last week. [I did not pass it]
If George hadn’t given up drinking, Emma would have left him. [George did give up drinking.]
See also: Problems with the Past Perfect