The history teacher lectured us every day about the importance of studying history, until we begged him to stop flogging a dead horse.
•Jill: I think I'll write the company president another letter asking him to prohibit smoking. Jane: There's no use beating a dead horse, Jill; he's already decided to let people smoke.
Смотреть больше слов в «Dictionary of American idioms»
ворошить прошлое You are flogging a dead horse - we are not interested in your project.
ворошить прошлое; стегать дохлую лошадь; заниматься бесполезным делом
зря тратить силы, решетом воду носить