问题
选择题
The factory produces half a million pairs of shoes every year,80%________ are sold abroad.
A．of them
B．which of
C．of which
D．of that
答案
答案：C
题目分析:考查定语从句。由结构判断后面是非限制性定语从句，排除A、D选项，而B选项形式错误，故答案选C。句意：这家工厂每年生产五十万双鞋，其中80%都被销售到了国外。