By 16:30, was almost closing time, nearly all the paintings had been sold.
A. which
B. when
C. what
D. that
网友回答
(答案→)A. which
B. when
C. what
D. that
解析：句意为：直到临近结束的16:30，几乎所有的油画才售完。“ was almost closing time”是个非限定性定语从句，且从句内缺少主语。所以用关系代词which. D项that不用于非限定性定语从句中。
【考点定位】考查定语从句关系词的选用。无论先行词是否是表时间，地点或原因的词，定语从句内成分残缺，少了主语或宾语，该选用关系代词。