What is the difference between past simple and past continuous tenses?
Just keep in mind
Past simple is always specific in time.
I have traveled to the USA two times. It is not specific information as you don't know when.
I traveled to the USA two times between 2003 and 2004. It is specific. It is past simple.
You asked me a question yesterday---specific by yesterday. past simple.
You were asking teachers several questions last day.
It does mean you asked but we don't know whether you stopped to question more! This is the sign of past continuous tense.
An action started in the past but we don't know whether was finished or not.
( according to Raymond Murphy)
When you were asking me the question, I read the news paper.
My perform was finished by when, but we don't know whether your questions to ask has been finished!
Hope it works.