by the time the freemen arrived at the building,the fire ———by the nearby citizens.（put）
问题描述：
by the time the freemen arrived at the building,the fire ———by the nearby citizens.（put）
消防员到达这栋大楼的时候,附近的市民已经把火扑灭了
答
填：had been put out
由主句的by the time和arrived可知,动作发生在过去的过去,用过去完成时
put out扑灭