【英语时差8,16】鞭策；督促（在线收听）

These days, we don't see many horse-drawn carriages in the streets, driven by coachmen who carry long whips. In the past, coach drivers used those whips to make their horses go faster. However, they did not let the whip lash actually touch or hurt the horses. Instead, just the loud sound of the whip cracking in the air just above the horses was enough motivation to make them go faster. A cracking whip can sound as loud as a gunshot. Because of that, when a boss, a supervisor, or a teacher wants people working under them to hurry up doing their work and produce excellent results, we often say they are "cracking the whip." They don't really have a whip in their hands, but their nagging and sense of urgency feels like they do.