By 17:30 was almost closing time nearly all the paintings had been sold.A. whichB. when

问题补充：

By 17:30, was almost closing time, nearly all the paintings had been sold.

A. which

B. when

C. what

D. that

答案：

(答案→)A. which

B. when

C. what

D. that

解析：考查从句，从句was almost closing time, nearly all the paintings had been sold缺少主语，所以在关系代词里选择，that不能引导非限制性定语从句，what表示…的东西，所以选A；句子意思“到17:30是关门时间，所有的画几乎被卖完了”