救援活动持续了三天。
与 rescue 用法非常相似的还有 aid，它也可以同时作名词和动词，同样可以说 come/go to one's aid。例如：
Soldiers went to the earthquake-striken area at top speed to aid the injured person.
军人火速赶往地震灾区展开救援。（*at top speed 火速）
The United Nations on Tuesday issued an urgent appeal for emergency aid to Haiti.
周二联合国发表了声明，呼吁（各方）对海地进行紧急援救。
The rescuers came to his aid in time.
救援者及时赶来给予他救助。
最后说一下，first aid 是“急救”的意思，我们每个人都应该掌握一些基本的急救措施，那样也许能在关键时刻拯救一条生命：
You should know how to do basic first aid.
你应该懂得如何实施基本的急救。