“how to do it和“what to do",请高手为我从句子结构上分析,

“how to do it和“what to do",请高手为我从句子结构上分析, 请问英语高手：What can I do?和 How can I do?哪句是正确的,要从句子结构上来分析 what to do和how to do it what to do和how to do how to do it和 what to do是什么来的?是不是宾语从句改为简单句? what to do和how to do it和when to do it中何时有 it? how to do it next还是what to do next 关于what to do ,how to do it. 关于how to do it what to do how to do it what to do的区别 如何讲解what to do结构和how to do 的区别 how to do it和what to do it的区别