Past Simple and Past Progresive

Use the Simple Past to express the idea that an action started and finished at a specific time in the past. Sometimes, the speaker may not actually mention the specific time, but they do have one specific time in mind.
Examples:
· I saw a movie yesterday.
· I didn't see a play yesterday.
· Last year, I traveled to Japan.
· Last year, I didn't travel to Korea.
· Did you have dinner last night?
· She washed her car.
· He didn't wash his car.

Use the Past Progresive to indicate that a longer action in the past was interrupted. The interruption is usually a shorter action in the Simple Past. Remember this can be a real interruption or just an interruption in time.
Examples:
· I was watching TV when she called.
· When the phone rang, she was writing a letter.
· While we were having the picnic, it started to rain.
· What were you doing when the earthquake started?
· I was listening to my iPod, so I didn't hear the fire alarm.
· You were not listening to me when I told you to turn the oven off.