问题补充：
--- When shall we leave?
--- As soon as I what I .
A. will finish; do
B. have finished, am doing
C. finish, will do
D. finish, do
答案：
A. will finish; do
(答案→)B. have finished, am doing
C. finish, will do
D. finish, do
解析：考察时态。句意：我们什么时候动身？——我一完成我正做的事情就出发。可知主句描述的是某个时刻完成的动作，从句描述的是正在进行的动作。故选B。
