The Past Continuous
The Past Continuous has two main uses:

Actions in progress at a moment in the past - often a background to a story.
I was sleeping when the phone rang.
I was sleeping at 3.30am this morning.
Note: it is possible that the action continued (here, I didn't wake up). But, it is possible that the action was interrupted at that moment (here, I woke up when the phone rang).
We also use past continuous when two longer events are happening at the same time
I was thinking about my holiday while I was teaching my class this morning.
We use be + verb-ing to make this structure. Remember to use contractions (wasn't, weren't) when speaking.
| Positive | Negative | Question | |
|---|---|---|---|
| I, he, she, it | I was working. | I wasn't working. | Was I working? |
| You, we, they | You were working. | You weren't working. | Were you working? |
Advanced uses of past continuous
Annoying habits: We usually use past simple for habits/repeated actions. But, if you are annoyed/amused, you can use the past continuous with 'always'.
He was always losing his wallet!
Past Continuous Exercises