Gun control is a subject Americans have argued for a long time.
A. of which
B. with which
C. about which
D. into which
网友回答
A. of which
B. with which
(答案→)C. about which
D. into which
解析：句意：对枪的控制是美国人一直争论好长时间的一个话题。这里是which引导的定语从句，先行词是subject，which在定语从句中作宾语。从句中的动词短语argue about sth争论某事；这里可以把介词放在关系代词的前面，与argue连用的介词是about，故选C。