--I called you yesterday evening but there was no answer.--Oh I’m sorry I in the shoppin

问题补充：

--I called you yesterday evening, but there was no answer.

--Oh, I’m sorry I in the shopping mall.

A. shop

B. shopped

C. was shopping

D. have shopped

答案：

A. shop

B. shopped

(答案→)C. was shopping

D. have shopped

解析：此句为过去进行时，所以用be+doing