Difference about Past Continuos, Past Perfect Continuos, Past Simple and Past Perfect.
Here I´m explaining the meaning of this tenses.
First of all I´m talking about Past Continuos which refers to events in the past is usually formed the background to the main events. Second of all there´s the Past Perfect Continuous that is to talk about events in progress in the past, seen from a point of view later in the past.
Past Simple to talk about completed actions or situations which happened at a specific time in the past. And at last, past perfect to talk about events in the past, seen from a point of view later in the past.