how 和what 用法的区别.

我不知道我该怎样帮助他=I don't know how to help him.
英语中how表示“怎样、如何”,常常用来提问表示状态、程度、方式等状语.
e.g.1.How is the weather today?-----It's rainy today.(提问状态)
2.How do you go to school?-----On foot.(提问方式）
3.How does Liu Xiang ran?----He runs very fast.（提问动作的状态）
4.How often do you have PE?------Twice a week.（提问频率）
英语中的what表示“什么”,常常用来对名词提问.
e.g.1.What is your English name?
2.What do you do after school?
3.What would like to eat this evening?
how后面要加宾语 I do not know how to do it what后面不用 I do not know what to do