"My father worked in his office every Monday."
Translation:Mon père travaillait dans son bureau tous les lundis.
Ouais me aussi. The first word my Pratique Larousse give for both each and every is chaque. When the example sentence pops up first in French, one learns. When the example sentence first pops up in English, one does the best one can, and one is always surprised when it is green rather than red.
The imparfait is used for habitual or repeated actions.