--- I can’t find Xiao Ping. Where did you see him this morning?
--- In the reading room he often studies in.
A. that
B. where
C. in which
D. the one
网友回答
(答案→)A. that
B. where
C. in which
D. the one
解析：考查定语从句，先行词是the reading room，定语从句中in缺少宾语用关系代词that，句意是：--我找不到小平，今天早上你在什么地方看见他的？--在他经常看书的图书馆。选A。