With time expressions such as always, constantly, continually and all the time, the past continuous can express frequently repeated past actions which annoy(ed) the speaker:
The past perfect continuous tense is used to express that an action started before a point in time in the past and that it was still in progress or it had just stopped. This point can be implied or expressed with a time expression or a clause with a verb in the past simple tense:
The past perfect continuous subjunctive can be used in the if-clause of a sentence in the third conditional to express an unreal action in the past which is imagined as continuous:
The past perfect tense is used to express that an action was completed before a point in time in the past. This point can be implied or expressed with a time expression or a clause with a verb in the past simple tense:
