—You were out when I dropped by your house. — Oh I in Zhongbai Supermarket with my parent

问题补充：

—You were out when I dropped by your house.

— Oh, I in Zhongbai Supermarket with my parents.

A. was shopping

B. had shopped

C. am shopping

D. have shopped

答案：

(答案→)A. was shopping

B. had shopped

C. am shopping

D. have shopped

解析：句意：---当我拜访你家时你不在家。---哦，我和我的父母正在中百超市购物。句中dropped用的是一般过去时，因此“拜访”的时候，正在超市购物，用过去进行时。故选A。