— When does your mother go shopping?—Usually Sunday mornings. A. in　B. on　C. withD. at

问题补充：

— When does your mother go shopping?

—Usually Sunday mornings.

A. in

B. on

C. with

D. at

答案：

A. in

(答案→)B. on

C. with

D. at

解析：考查情景交际和介词的用法。“你妈妈什么时候去购物？”“通常在周日上午。”具体的一天或一天的上下午晚上，用介词on，例如：on a cold night。故选B。