Use the Past Continuous for the longer action that was in progress, and the Past Simple for complete actions, including the short one that interrupted it: I was cooking when she called.
Same situation, two choices. Pick an example.
She called at 8.
A finished action, start to end. In a story, Past Simple actions move the plot forward.
I was cooking when she called.
The action was in the middle of happening. It sets the scene; we don't see it start or end.
| Rule | Past Simple | Past Continuous |
|---|---|---|
| Form | I worked · Did you work? | I was working · Were you working? |
| Focus | The complete action | The action in progress |
| In a story | Events: what happened next | Background: the scene |
| Signal words | yesterday, then, when + the short action | while, at 10 pm, all evening |
I _____ TV when the lights went out.
Paste an email or an essay. Clarigram marks the mistakes you actually make, shows the rule behind each one as a picture, and builds your practice from them.
Use while before the longer action in progress (while I was driving) and when before the short one (when the phone rang).
Yes, for two longer actions happening at the same time: While I was cooking, he was setting the table.