Question

The new buyer identified a dozen new sources for the material, ___________ proved to be reliable．

A．most of them

B．most of which

C．most of whom

D．most of those

Answer 1

B

试题分析：句意：新的买方确定了十几个新的来源为材料，大部分被证明是可靠。先行词是物the material，应该用which做介词宾语，引导非限制性定语从句，whom代人，其他表示定语从句的关系词，故选B。
考点: 考查定语从句的用法。