n. a fortified defensive structure
n. 城堡, 要塞
vt. 筑要塞, 以要塞防守
1. The ancient fortress was built on a high hill to protect the city.
古老的堡垒建在高山上，以保护城市。
2. Tourists visit the fortress to learn about its history and enjoy the views.
游客参观堡垒，以了解它的历史并欣赏美景。
3. The soldiers defended the fortress during the long battle.
士兵们在漫长的战斗中保卫了堡垒。