1. An event in the past which happens before another event in the past, where there is no time expression to make this clear.
By the time I got to the station, the train had left. The train left five minutes before I got to the station. 2. Past perfect continuous (progressive).
The contrasts between past simple and past continuous can be made in past perfect tenses for events further back in the past.
I had been living in a bed-sitter up to then. While I had been talking on the phone, Jimmy had escaped. 3 Past perfect is not used simply to describe an event in the distant past. There must be another past event, less far away in the past, with which it contrasts.
She sad that she had met him before on holidays at the seaside.
4. Used to and would
1. Used to often contrasts with the present. The contrast may be stated or understood. I used to go swimming a lot (but I don't now). The negative form is either: I didn 't use to or I used not to 2. Would is used to describe repeated actions, not states. It describes a habitual activity, which was typical of a person. Every week he'd buy his mother a bunch of flowers. Used to would also be possible here. Compare:
I used to like cowboy films
These describe events intended to take place, but which did not happen.
I was going to phone you, but I forgot. Jack was to have taken part, but befell ill. I was thinking of going to Italy this year, but I haven't decided. I was about to do it, but I started doing something else.
