问题
选择题
It suddenly occurred to him________he had left his keys in the office. (2012·江西，25)
A．whether
B．where
C．which
D．that
答案
答案：D
解析 It occurs/occurred to sb. that...某人想到/想起。it是形式主语，主语从句成分完整，不能用连接代词which引导，whether与where不符合句意。故选D项。