what fine weather it is!为什么不用how fine

fine weather是名词，所以用what，如果要用how fine 句子就要改成
How fine the weather is!

how 改为 what 或者去掉it
感叹句的形式：How+形容词+主语+谓语，例如How beautiful the girl is！
What+a/an+形容词+可数名词单数+主语+谓语，例如：What a beautiful girl she is!
What+形容词+不可数名词或可数名词复数+主语+谓语
例如：What beautiful flowers they are!

可以！但句式不同
What +名词（词组）+主语+ 谓语
How +形容词/副词+主语+谓语
What fine weather it is != How fine the weather is!

what修饰wheather，is是系表结构里的系动词，不是谓语。。。。。

what 最终修饰名词，how最终修饰形容词/副词
What clean water it is.
How clean the water is.
What a beautiful city it is.
How beautifu the city is .