为什么能说What fun it is to do sth.却不能说How fun it is to do sth.

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造句 It is fun to do sth.造句. 不是说what+n.+主谓吗,但为什么说是what fun it is to do sth呢? what great fun it is+to do sth 吗 It is fun to do sth.句型fun的词性 It is fun to do sth对,还是It is fun to doing sth It is fun?到底是It is fun to do sth 还是It is fun doing sth?It is it is a great fun to do sth. 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 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's fun to do sth.中的fun什么词性