感叹句

感叹词what，how

what有两种词性：名词、形容词。
how只有一种词性：副词

what+名词短语+（主+谓）

What a good boy he is!
What god news it is!
What good weather!

How+动词 or 形容词 or 副词

How good (the boy is)!
How fast he runs!