directory sorting

例句：

1. 1. The library has a directory of all the books in its collection.
   图书馆有一个所有藏书的目录。
2. 2. She consulted the directories for information about the area.
   她查阅了目录以获取该地区的信息。
3. 3. The directories were organized alphabetically by subject.
   目录按主题字母顺序组织。