constantly evaluate and update the periodical maintenance task works and the systems plants operation and if necessary modification for improvement that approved by engineering hod only
不断评估和更新定期维修工作和系统设备的运行情况，如有必要，仅由工程主管批准进行改进
以上为机器翻译结果，长、整句建议使用 人工翻译 。