-- I don’t know with this problem. It’s too hard.
--- You can ask Mr Wang for help.
A. which to deal
B. when to deal
C. what to deal
D. how to deal
网友回答
A. which to deal
B. when to deal
C. what to deal
(答案→)D. how to deal
解析：D 考查固定短语。“我不知道如何处理这个问题。”宾语是this problem，故不用what做do的宾语，排除C，选D。