Another reason he didn’t mention is the poor quality of the buildings worsened the damage.
A. why; because
B. for which; that
C. that; that
D. which; because
网友回答
A. why; because
B. for which; that
(答案→)C. that; that
D. which; because
解析：考查定语从句和表语从句：句意：他没有提到的另外一个原因是建筑质量差使破坏更加严重。第一空填定语从句，先行词是reason，定语从句缺少宾语，用that或which引导定语从句，第二空是表语从句，当主语是the reason的时候，表语从句用that连接。选C。