An action going on in the given period of time in the past.
Actions characterizing the person denoted by the subject, bringing out the person's typical traits.
An action which began before the given past moment and continues into it or up to it. (with stative verbs, with some dynamic verbs of durative meaning, in negative sentences).
An action which was in progress just before the given past moment and it effects the past situation in some way.
To indicate a future action viewed from the past. An action which was supposed to take place due to one's previous decision.
An action which was going on in the given moment in the past.
An action accomplished before a given past moment and viewed back from the given past moment.
An action which began before the given past moment and continues into it or up to it.
A future action viewed from the past in adverbial clauses of time introduced by conjunction ""when, before, after, as soon as, till and until"
