Can you tell me what you when the teacher came into the classroom?A. didB. doC. are doing

问题补充：

Can you tell me what you when the teacher came into the classroom?

A. did

B. do

C. are doing

D. were doing

答案：

A. did

B. do

C. are doing

(答案→)D. were doing

解析：句意；你能告诉我当老师进入教室时，你正在做什么吗？结合语境可知宾语从句中描述的是过去某时正在进行的动作，故用过去进行时态。选D。