must do best to serve the people

问题描述:

must do best to serve the people
a.one...his
b.one...her
c.one...one
d.ones...ones'
我真服了这些英语题了,

选a
one must do his best to serve the people
一个人要最大程度服务他人
one做不定代词好理解
后变为什么不选one呢 因为要构成one‘s best所属格 一个人最大的..
而ones一般代复数