enumeration of labelled trees

例句：

1. 1.The teacher enumerated all the students in the class.
   老师列举了班上所有的学生。
2. 2.They enumerated the items on the list and checked them off.
   他们把清单上的物品一一核对并勾选。
3. 3. The enumeration of the data was essential for the analysis.
   数据列表的编制对于分析至关重要。