how修饰的是形容词或者副词，how与形容词和副词连用时，形容词或副词紧接在how之后。
例：How beautiful the pen is!How lovely the baby is!
How nice!How well she plays!
what修饰的是名词，what与名词单数连用时往往在what之后跟不定冠词a或an.
例：What a beautiful picture it is!What an ugly man he is!
What a nice hat she wears!
它们的区别在于：how是疑问副词，不能作宾语；what是疑问代词，可以作宾语。
how 是副词后可接形容词或副词
如How clever she is！或How clever a girl she is !
what是形容词，形容词后要接名词或名词性质的词，如：what fun it is！
what在从句中作主语，宾语，表语；How_诖泳渲凶髯从铩