What a blue sky!中的sky为什么能加a?

What a blue sky!中的sky为什么能加a?感叹句中不是可数名词前加a吗? 用a deep blue sky造句 In a blue sky ,live a blue life. In a blue sky ,live a blue life.. what the sky is blue blue sky BLUE!SKY The sky looks blue.为什么looks要加s? 关于英语中的感叹句How＋形容词＋主语＋谓语那为什么嚒How blue the sky is sky 和 is 中间不加 looking at the moon through a clear blue sky 翻译英语句子"why is the sky a blue color?" The sky still as blue,just a many