Zhouqu, Gansu was attacked by such a terrible mud-rock flow few residents had ever experienced before.
A. as
B. which
C. where
D. that
网友回答
(答案→)A. as
B. which
C. where
D. that
解析：考查定语从句，先行词为a terrible mud-rock flow，从句中few residents had ever experienced后缺少宾语，因为先行词前有such，所以后应用关系代词as,选A。