Explain how the pluperfect tense is formed

In French, we use the pluperfect tense when one action occurred before another action. In English, we recognise the pluperfect by "had + the past participle." For example:"She had already prepared dinner when the children returned from school"In order to put the pluperfect into French, we simply take the imperfect tense of "avoir" and follow it with the past participle of the verb.In this case, "Déjà elle AVAIT PRÉPARÉ la nourriture quand les enfants rentraient"We need to be careful with verbs that take être in the passé composé, however the only difference is that the rule is the imperfect of être followed by the past participle of that verb.