My brother’s bedroom is always a mess, and he can never find anything, is very frustrating.
A. where
B. whom
C. when
D. which
网友回答
A. where
B. whom
C. when
(答案→)D. which
解析：句意：我哥哥的卧室总是一团糟，他从来找不到东西，这真令人使人沮丧的。这里用which引导非限制性定语从句，指代前面的句子，which在定语从句中做主语，所以选D。