PAST SIMPLE
The old man often visited me.
I noticed this charming shop girl each time I went to buy something
I heard a strange sound, looked back, and saw a huge cat sitting on the table.
Did you wash your hands?
Did they sign the contract?
PAST CONTINUOUS
When you called I was taking a shower.
Charlie and me were already driving home when the engine suddenly stopped.
I was sleeping when someone knocked at the door.
In the morning our elevator was not working.