Past Simple	Past Continuous
V2 a single action We won! a row of actions I went to the shop and bought a phone.	was/were + Ving an action in progress in the past I was sleeping at 11 p.m. last night. background information, descriptions The sun was shining and the birds were singing. We were walking in the park.

Note:

1) 2 actions in progress at the same time (Past Cont + while Past Cont)

While my cat sleeping I was studying.

2) 1 action in progress (Past Cont) interrupted by another SINGLE action (Past Simple):

While I was walking the park it started raining.

When I was watching TV, my mom came home.