My ruler is longer than _____?

选A.因为这里要用 名词性物主代词 .我的尺子比他的（她、你的）长，后边是人，就应该用宾格，那么主格:I you he she you we they
宾格:me you him her you us them
形容词性物主代词:my your his her your our their
名词性物主代词:mine yours his hers yours ours theirs
只能在最后里边挑一个最合适的，就是his。

A
主格:I you he she you we they
宾格:me you him her you us them
形容词性物主代词:my your his her your our their
名词性物主代词:mine yours his hers yours ours theirs
形容词性物主代词后是名词；
名词性物主代词后无名词

his选A
在这里要用名次性物主代词
B和C都是形容词性物主代词
A的HIS代他的尺子

选A his，考查物主代词的性质，
his在这里相当于his rulers若其他选项改为yours hers也是对的

A
因为这里要用 名词性物主代词

A.his