fire的复数形式是什么

例句：

1、It took two hours to put out the fire. （用作名词）

用了两小时才把火扑灭。

2、The cause of the fire is not yet known. （用作名词）

火灾的原因尚不清楚。

3、The officer ordered his men to fire. （用作动词）

军官下令士兵射击。