问题补充：
It’s nice to see you again. What since we last met?
A. have you done
B. had you done
C. have you been doing
D. did you do
答案：
A. have you done
B. had you done
(答案→)C. have you been doing
D. did you do
解析：考查时态。句意：很高兴又见到你。自从我们上次见面你一直在做什么？结合语境可知下文描述的是现在已经完成的动作，瞬间动词do不能和表示一段时间的时间状语连用，故选C。
