trench line

例句：

1. 1. The soldiers dug a trench line to protect their position.
   士兵们挖了一条战壕线来保护自己的位置。
2. 2.The enemy launched an attack from the trench line.
   敌人从战壕线发起了攻击。
3. 3.The trench line was the first line of defense against the enemy's advance.
   战壕线是抵御敌军进攻的第一道防线。