Past tense -- past perfect progressive (4)

Forms:  I had been working.

The past perfect progressive is used to talk about actions or situations which had continued up to the past moment that we are thinking about, or shortly before it. 
   When I found Jane, I could see that she had been crying.

Compare progressive and simple

            progressive                                                                       simple
more temporary actions and situations                  longer-lasting or permanent situations          

emphasise the continuation of an activity              emphasise the idea of completion

some verbs are not normally used in
 progressive forms