blueline

例句：

1. 1.The blueline is a symbol of national pride.
   蓝线是民族自豪的象征。
2. 2.The soldiers stood at the blueline, ready to defend their country.
   士兵们站在蓝线上，准备保卫他们的国家。
3. 3. The blueline was a crucial part of the battle plan.
   蓝线是战斗计划中至关重要的一部分。