When we got there, the fire brigade had already arrived and started to work.

fire 的意思是"火"，这里指与火灾相关的。 brigade 来自法语，原指"军队中的旅级单位"，后来引申为"有组织的专业队伍"。 fire brigade 是英式英语中对"消防队"的称呼，在美式英语中对应的表达是 fire department。