The future perfect continuous tense is used to express events that will start before a point in time in the future (or have already started) and will still be in progress at that point:
By tomorrow, it will have been raining for four days.
Soon, he'll have been running for 4 hours.
The past continuous is used to describe actions which continued over a period of time in the past. This period can be expressed with a time expression or a clause with a verb in the past continuous tense. In this case the two actions were happening simultaneously:
The past continuous tense is used to refer to actions that were in progress at or around a specific 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:
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:
