筑城堡防御

例句：

1. 1. The soldiers stood their ground and defended the city against the attackers.
   士兵们坚守阵地，保卫这座城市免受攻击者的攻击。
2. 2. The policemen were ordered to defend the public order.
   警察被命令维护公共秩序。
3. 3. She defended her decision by pointing out the facts.
   她通过指出事实来捍卫自己的决定。