博物馆展出的这颗铁球是18世纪从大炮发射出的炮弹。

The iron ball displayed in the museum is an 18th-century ___cannonball fired from a cannon.

他在泳池边做了一个完美的炮弹式跳水，溅起了巨大的水花。

He performed a perfect ___cannonball from the pool edge, creating a huge splash.

那个棒球手击出的球像炮弹一样飞速穿过球场。

The baseball player hit a ___cannonball that flew across the field at incredible speed.