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

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 为什么能说What fun it is to do sth.却不能说How fun it is to do sth. It is fun to do sth.句型fun的词性 it is fun to do 还是 doing? It is fun to do sth造句 It is great fun to do ... It is fun to do sth.造句. what fun it is to listen music 这里的fun为什么不能是形容词用how fun. what fun it is to do怎么造句 what great fun it is+to do sth 吗 为什么是what fun it is to. what fun it is to swim 为什么不能用how?