Question

Mr. Green has two sons, one of _____ working as a bus driver now.

A．who

B．whom

C．them

D．whose

Answer 1

C

考查独立主格结构。根据one of _____ working as a bus driver now中没有谓语动词可知不是从句，them指代前文提到的两个儿子，选项ABD一般用于引导定语从句，故选C。格林先生有两个儿子，他们其中一个现在做公交司机。