operation
英 [ˌɒpəˈreɪʃn] 美 [ˌɑːpəˈreɪʃn]
n.
活动;手术;(有组织的)行动;(包括许多部分的)企业;公司;（工商业）活动，业务;运算;运转;军事行动
复数： operations
记忆技巧：oper 工作 + ation 行为 → 操作
例句
The system has been in operation for six months.
这个系统已经运行六个月了。
His quality of life has improved dramatically since the operation.
手术后他的生活质量大大改善了。
The first 24 hours after the operation are the most critical.
病人手术后头24小时是最危险的。
