Voted Best Answer
Jan 23, 2012 - 09:28 PM
It boils down to what the helping verb is that is used in constructing the passé composé: if the verb uses être, then the participle is treated as an adjective that must follow the gender/number agreement rules; if the verb uses avoir, the participle does not change. For example, compare these: Jean est allé au supermarché. Jeanne est allée au supermarché. Les femmes sont allées au supermarché. Since the helping verb is être, the participle (allé) needs to match the gender and number of the subject of the sentence. However, compare these: Jean a acheté des pommes. Jeanne a acheté des pommes. Les femmes ont acheté des pommes. Since the helping verb is avoir, the participle (acheté) does not change.