Past Simple-Past Continuous, zastosowanie

Tak dla pewności, bardziej chodzi o przyporządkowanie niż błędy w zdaniach, część z ich jest żywcem przepisana

Past Simple:
Actions which happened one after the other
I got up early morning, had a shower and went to work.


Past Continuous+Past Simple
A past action in progress interrupted by another past action
I was having a bath when my doorbel rang.

Past Continious
Past actions of a certain duration which happened at the same time
rozumiem, że certain duration oznacza pewny tj. jakiś czas trwania?
Bill was watching TV while his wife was getting dressed
The sun was shining and the birds were singing

Past Simple
An action which happened at a definite past time
I heard my dog's bark 5 min. ago

Past Continuous
Giving a background description to events in a story-Dawanie opisu tła wydarzeń w historii ?
As she was running in the marathon, the crowds were cheering enthusiastically.
Tego zastosowania nie do końca rozumiem.

ok

ostatnie uzycie to typowy wstep do opowiadania:
ptaszki spiewaly, samochody jezdzily po ulicach, ludzie szli do pracy. Nagle - i od tego miejsca Past Simple