The immediate parent folder of the lowest subfolder must exist. 最低子文件夹的上面一层父文件夹必须存在。
A pie graph for a folder or disk is created, and any subfolder pie slice can be clicked to produce a graph of that folder. 一个文件夹或者磁盘的饼形图被创建，并且任何子文件夹的饼形图块能够被点击以生成一个那个文件夹的图表。
