In the exercise entitled "A Book Lover," there is a phrase "...rien qu'en observant ses grands frères et sœurs." When I entered that spelling, the s's at the ends of "frère-" and "sœur-" were marked as incorrect even though they were present in the correct example.
In passing, if Damien indeed only had one brother and one sister, would we have to say 'son frère et sa sœur'?
Thanks a lot.
