His parents were teachers in that school, lost their lives in order to save their student

His parents were teachers in that school, lost their lives in order to save their students in the earthquake.
A. none of them
B. both of them
C. none of whom
D. both of whom

A. none of themB. both of themC. none of whom(答案→)D. both of whom解析：句意：他的父母都是这个学校的老师，他们两个在那次地震中为了挽救学生而失去了生命。因为逗号的前后都是句子，所以缺少连词，them是代词，不是连词，故排除AB；none 表示三者以上都不，这里指父母两个人，所以排除C，both表示两者都，both of whom lost their lives in order to save their students in the earthquake. 是定语从句，修饰先行词parents，whom既代替parents又能起连接的作用，正符合题意，故选D。

我学会了