---- you were arguing about last night has been settled.A that B which C it D what

问题描述:

---- you were arguing about last night has been settled.A that B which C it D what

D what
句子里缺少主语,所以这是一个主语从句,what you were arguing about意思是你们所争论的事情,其余三个选项在这里都不能作主语.