flog a dead horse

例句：

1. 1. The coach flogged the team for their poor performance.
   教练因为球队表现不佳而鞭打了他们。
2. 2. He was flogged by his boss for being late to work again.
   他因为再次迟到而被老板鞭打了。
3. 3. The punishment was a flogging in the public square.
   惩罚是公开广场的鞭刑。