问题补充:
-- your homework yet?
-- Not yet. I it.
A. Have you done; am doing
B. Did you do; am doing
C. Have you done; did
D. Did you do; did
答案:
(答案→)A. Have you done; am doing
B. Did you do; am doing
C. Have you done; did
D. Did you do; did
解析:句意:你完成作业了吗?还没有。我正在做。由yet可知该句用现在完成时态,结合情景知后句用现在进行时态。所以选A。