signal mine

例句：

1. 1. The soldiers were instructed to place the signal mines in strategic locations.
   士兵们被指示在战略位置放置信号地雷。
2. 2. The mine was a major factor in the battle, causing significant damage to the enemy forces.
   这个地雷是战斗中的一个主要因素，对敌军造成了重大损害。
3. 3. The mine was detonated by a remote control device, creating a loud noise that alerted nearby soldiers.
   这个地雷是通过遥控装置引爆的，发出了响亮的声音，使附近的士兵警觉起来。