问题补充：
Have you ever noticed the house, windows are always closed?
A. where
B. which
C. when
D. whose
答案：
A. where
B. which
C. when
(答案→)D. whose
解析：考查非限制性定语从句。the house是先行词，which指物，作主语或宾语；whose作定语；where和when作状语；根据从句中的名词windows可知，缺少定语。whose windows相当于of which the windows或the windows of which。故选D。
