问题
选择题
Gun control is a subject ______ Americans have argued for a long time.
A．of which
B．with which
C．about which
D．into which
答案
答案：C
考查定语从句，先行词是Gun control，指物，关系词在从句中做介词的宾语，介词前置，介词与从句动词构成搭配argue about sth，选C。