A single action which took place in the past.
A succesion of actions in narration.
An action which occupied a whole period of time now over.
Recurrent action in the past.
Permanent actions which indicate continuous uninterrupted procces in the past, giving a general characteristic of the persin or thing denoted by the subject.
You often mentioned you in your letter.
We stayed in the garden for a long time.
I knew they loved each other, but they always quarrelled.
Things came to a crisis in July.
I found some matches, climbed on the table, lit the gas lamp, then settled down to read.
