B2_Past Perfect Simple and Past Perfect Continuo ...

When we say how many actions had been completed

actions or situations that finished some time before other actions in the past

actions that were in progress up to a time in the past

Often with the following time expressions: all day / night / week, for years / a long time / ages, since, how long … ?

when we say how long an action lasted up to a point in the past

actions completed some time in the past that had a result later in the past

Often with the following time expressions: before, after, when, already, for, for a long time, for ages, just, never, once, since, yet, etc.

actions in progress up to a point in the past, and having an immediateresult