Gun control is a subject Americans have argued for a long time.
A. of which
B. about which
C. with which
D. into which
网友回答
A. of which
(答案→)B. about which
C. with which
D. into which
解析：句意：枪支的控制是美国人争论了好长时间的话题。这里使用了定语从句，先行词是subject，关系代词前用什么介词要取决于本句中的“argue”。argue about sth.选B。