请教初中英语Miss Smith is a friend of my mother's.这个句子对吗?用of 时后面还要

miss smith is a friend of mary‘s mother’s Miss Smith is a friend of A．Mary's mother's B．Mary's mother 1．Miss Smith is a friend of _____ ． Miss Green is a friend of（ ） A.mary's mother's B.mary's moth Miss Green is a friend of _______.A.Mary’s mother’s B.Mary’s he is a friend of my mother与he is a friend of my mother’s有什么 Miss Green is a friend of Mary's mother's 这里为什 He is a friend of my mother 是a friend of my mother对,还是a friend of my mother's对? 初三一道英语题Miss Green is a friend of（ ）A.mary's mother's B.mary' （ ） Mr Smith is a friend of ————.A.my uncle B.my uncle’s C.m a friend of my mother's 等于什么?