was studying, studied
Je pensais que tu étudiais le français.
I thought you were studying French.
Je me suis endormi pendant que j'étudiais sur mon bureau.
I fell asleep while studying at my desk.
Saviez-vous que j'étudiais chez Mme Strong avant de venir ici ?
Did you know that I studied with Mrs. Strong before coming here?
— L'Histoire personnelle de David Copperfield (2019)
J'étudiais la journée, le soir, je travaillais.
I studied during the day, and in the evening, I worked.
— Oh Boy (2012)