投石机

例句：

1. 1. The ancient citywall was built to protect the city frominvaders.
   这座古老的城墙是为了保护城市免受侵略者的攻击而建造的。
2. 2. Thearchaeologists used a stone throwerto uncover more about the ancient civilization.
   考古学家使用投石器来揭开更多关于古代文明的信息。
3. 3. The soldiers were trainedto use their stone throwers effectively inbattle.
   士兵们被训练得在战斗中有效地使用他们的投石器。