—Have you solved your problem ?—No I really don’t knowA. how to do with B. what to do C.

问题补充：

—Have you solved your problem ?

—No, I really don’t know

A. how to do with B. what to do C. what can I do

答案：

解析：考查疑问词+不定式作宾语。句意：你解决了你的问题了吗？没有，我真的不知道怎么做。所以选B，A项how不能与do with连用。C项应用陈述句语序。