Bonjour! Here are two consecutive sentences from my French study workbook: "J'étais bon élève. J'ai toujours été un bon élève." My question is: Why is the article "un" used in one sentence and not the other? Is it simply optional in both cases, or is there some kind of grammatical rule involved? "J'étais bon élève" seems to follow the same form as "Il est ingénieur" to describe a role or profession, but I have no guess about the other sentence. Merci d'avance!