why do you say

why do you say there isn't a single book in his house as sa maison, how do you say her house? merci

Hi - The possessive adjectives and pronouns lesson comes up in Lesson 12.7. It's *sa* because maison is feminine, so it would still be *sa* if it's *her* house versus *his* house; the gender agreement is with the object/possessed thing, not the gender of the owner. The examples they give are: C’est la sœur d’Eric - It's Eric's sister. C’est *sa* sœur - It's his sister. C’est le chapeau de Pauline - It's Pauline's hat. C’est *son* chapeau - It’s her hat. It's also mentioned in Lesson 2.11 on possessive adjectives for describing masculine/feminine nouns.

salut toru25 et merci . I should have know that was sa maison , sometimes i get confused by this French but I still am trying. merci

Salut, GaryWages, je vous en prie.