The factory produces two million pairs of shoes every year, half are sold abroad.
A. of which
B. which of
C. of them
D. of that
网友回答
(答案→)A. of which
B. which of
C. of them
D. of that
解析: 本题考查定语从句。“逗号”不能连接两个句子,所以所选之词应是连词,排除C项;that不能引导非限制性定语从句,排除D;介词应用在of前。