Simple past and past continuous

One action followed by another:

Troy finished the book before he went to bed.
I went to the bank after I got paid.

An action that started before a specific time, and continued:

At 7 o'clock last night I was watching television.
When you saw me, I was waiting for my father.

One action interrupted by another:

I was taking a shower when the phone ring.
Paula had an accident while she was driving to work.