(English version follows Chinese Part)
之前已经利用WP-dTree插件，将分类目录变成树状，实现了图书索引的功能，本次工作是往分类目录里录入图书分类法。
使用的是国际十进制图书分类法(UDC)，直接使用官网(戳这)的树结构，恰巧其包含了多种语言，尤其是英文和中文。所以主要工作差不多就是复制粘贴了。
另外在图书馆的侧边栏添加了UDC和中图分类法(CLC)的官网链接，方便查询完整结构。
In past work, plugin WP-dTree has been used to implement library index functions replacing Categories. This time, the task is input the library classification.
I chose the Universal Decimal Classification (UDC) instead of Chinese Library Classification (CLC), so I copy the same classification tree-structure from the office website of UDC (Link). Luckily, they have varieties of language versions including Chinese and English. Just do it.
Adding office website links of UDC and CLC(Link) to the sidebar so that visitors can search for complete library classification structure.