不是说what+n.+主谓吗,但为什么说是what fun it is to do sth呢?

不是说what+n.+主谓吗,但为什么说是what fun it is to do sth呢? 为什么能说What fun it is to do sth.却不能说How fun it is to do sth. what great fun it is+to do sth 吗 为什么是what fun it is to. how fun it is to do … what fun it is to do… 为什么要用后者,fun如果当形容 It is fun to do sth造句 It is fun to do sth.造句. what fun it is to do怎么造句 it is +形容词+to do sth ,为什么有些资料上是it's fun +to do sth,fun是形容词吗 为什么说what fun it is!而不用how fun it is?这是什么句型? It is fun to do sth.句型fun的词性 what fun it is to swim 为什么不能用how?