如何解释英文的Operation?

operation
KK:[]
DJ:[]
n.
1.操作;运转[U]
The operation of this machine is simple.
这个机器的操作很简单.
2.经营;营运[U]
The operation of a railroad needs many men.
铁路的营运需要很多人.
3.作用;效力[U][C]
The operation of natural law is constant.
自然法则的作用是永恒的.
4.活动;工作;事[C][P1]
The rescue operation lasted three days.
救援活动持续了三天.
5.【医】手术[C][(+on/for)]
Her father underwent a major operation last week.
她父亲上周动了一次大手术.
6.军事行动,作战[C][P1]
The general was in command of operations in the north.
将军负责指挥北方的作战行动.
7.交易,买卖[C][P1]
He continued his operations in cotton futures.
他继续进行棉花期货交易.
8.【数】运算[C]
9.(尤指法律文件的)生效[U]