sleeper drill

例句：

1. 1. The military conducted a sleeper drill to test the effectiveness of their new tactics.
   军队进行了一次模拟战斗训练，以测试他们的新战术的效果。
2. 2. The soldiers underwent a sleeper drill to improve their combat readiness.
   士兵们接受了一次模拟战斗训练，以提高他们的战备状态。
3. 3. The drill was designed to simulate real-life combat scenarios and enhance the soldiers' survival skills.
   这次演习旨在模拟真实的战斗场景，以增强士兵的生存技能。