The past progressive tense is used to demonstrate an action that was happening in the past for a period of time in a particular context. The context can be a specific time or another action.
Structures:
Subject + was/were + verb + ing + . . . . . a specific time
Alex was sleeping yesterday at 6.30 AMI was cleaning the dishes at around 5.30-6.30 yesterday.
When + subject + simple past tense + subject + was/were + verb+ing . . . .
When I went out, you were shouting from behind.When Alex came, I was sleeping.
Subject + was/were + verb+ing + when + subject + simple past tense . . . .
You were shouting from behind when I went outside.I was sleeping when Alex came home.