big gun

例句：

1. 1.He's a big gun in the industry.
   他在业界是个大人物。
2. 2. The big gun is always ready to fire at any time.
   这个大家伙随时准备开火。
3. 3. They used a big gun to shoot down the enemy plane.
   他们用一把大枪击落了敌机。