英语问题she doesn't know ( )

问题描述:

英语问题she doesn't know ( )
she doesn't know ( )
A,what to do
B,what to do it
为什么?
我没看错答案,我对此也很奇怪

那肯定是答案错了.有几种可能
she doesn't know what to do.
she doesn't know how to do it.
she doesn't know what to do with it.