满分15分阅读下面短文,在空白处填入1个适当的单词或括号内单词的正确形式。Xuan paper, known as one of the Four Treasures of Study, first came into 6/ existenceexist) inXuan Prefecture in the Tang dynasty. The traditional skill of making the paper 62 y hand has beenpassed down through generations. The process takes as many as 18 steps, all of 63 whihlevel of delicacy