Question

Why did you speak to Peter that way? Don't you know he is an old friend of

A.my brother
B.my brothers
C.my brother's
D.my brothers's 为什么选c我觉得应该选A的，

Answer 1

c 你得复习下 那个什么双重所有格了 名词 +of +名词所有格。。
of+ -'s结构就做双重属格（double genitive)，如a friend of my father's （我

父亲的一个朋友)中的of my father's

Answer 2

原句：my brother's old friend is he。
宾语前置：he is an old friend of my brother's （old friend）
再加上反问 Don't you know he is an old friend of my brother's

Answer 3

我也觉得选A