Clearly, this is not the first time for the US navy has conducted surveillance in that area of the South China Sea, as the Pentagon said the Impeccable was conducting routine operations.

• 很显然；这不是对于美国海军第一次在中国南海的那个地区(已经)进行监视；随着五角大楼说无暇号(正在)处理例行任务.