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!
What cold water it is!