What you at 10:00 last night?A. did; doB. were; doingC. was ;doingD. have; done

问题补充：

What you at 10:00 last night?

A. did; do

B. were; doing

C. was ;doing

D. have; done

答案：

A. did; do

(答案→)B. were; doing

C. was ;doing

D. have; done

解析：根据last night可知，本句的时态是过去时，所以排除D；又因为10点，所以本句应该是过去进行时，应该选BC；根据you，我们知道应该用were。所以本题选B。