有围墙的城

例句：

1. 1. The city has a wall around it to protect it from the outside world.
   这个城市有一道墙围绕它，以保护它免受外界的影响。
2. 2. The prison is surrounded by high walls and barbed wire.
   监狱周围是高墙和铁丝网。
3. 3. The forest was enclosed by a large lake, providing a natural barrier.
   森林被一个大湖所包围，提供了一个天然的屏障。