问题补充:
Can you tell me ?
A. what are they doing that for
B. why they are doing for
C. why are they doing that
D. what they are doing that for
答案:
A. what are they doing that for
B. why they are doing for
C. why are they doing that
(答案→)D. what they are doing that for
解析:可联系答.案.网客服索取。