cannon cracker

例句：

1. 1.The cannon was fired to scare offthe enemy.
   大炮被发射以吓退敌人。
2. 2. The cannons were used tomark the boundaries of the battlefield.
   大炮被用来标记战场的边界。
3. 3. The cannons were a symbol of power andstrength in ancient times.
   在古代，大炮是力量和强大的象征。