Can you tell me when I called you?A. what were you doingB. what are you doingC. what you

问题补充：

Can you tell me when I called you?

A. what were you doing

B. what are you doing

C. what you were doing

D. what you are doing

答案：

A. what were you doing

B. what are you doing

(答案→)C. what you were doing

D. what you are doing

解析：英语宾语从句中一般为陈述语序。联系下文，当我打电话给你时，可知宾语从句中描述的是过去某时正在发生的动作，用过去进行时态。故选C。