a friend of my还是a friend of mine

a friend of my还是a friend of mine 英语翻译a friend of my father's还是a friend of my father,如何辨别, “A friend of my sister”表达正确吗?还是应该是“A friend of my sister's”? 是a friend of my mother对,还是a friend of my mother's对? a friend of Tom表达对,还是a friend of Tom's对a friend of my father对，还是a friend of my father's对 She is a friend of my正确还是She is a friend of mine正确? 是a firend of my english teacher 还是 a friend of my english teacher's 为什么 a my friend还是my a friend ,为什么 he was___in the childhood.填写my close friend还是a close friend of mine? a friend of her还是a friend of hers a friend of mine=?my friends He is a friend of my father正确还是He is a friend of my father's正确?迷惑哦,最好能解释为什么. a friend of my father和a friend of my father`s的区别? a friend of my father? a friend of my father's?两种说法哪个对? a friend of my brother和a friend of my brother's 有什么区别? a friend of my brother 还有a friend of my brother 两者什么区别? a friend of Lily还是Lily's Mike is________.A a friend of me B one of my friend C one of my friend D the friend of my