what后跟名词或带形容词的名词；how后跟形容词或副词：
How happily the students are playing the games!
What fun it is to play games!
What a nice day!How happily ，为什么是副词呢，happy不行吗因为是修饰动词短语：play the games，happy是形容词，修饰名词希望对你有启发，如对你有帮助，请记得及时采纳