“承认失败”常见的英文表达有：
admit defeat：这是最直接、常用的说法。例如：After several failed attempts, he finally admitted defeat.（经过几次失败的尝试后，他终于承认了失败。）
acknowledge failure：侧重于对失败这一事实的确认或认可。例如：The team had to acknowledge failure after losing the championship game.（在输掉冠军赛后，这支球队不得不承认失败。）
concede defeat：带有“无奈地、不得不地承认失败”的意味。例如：With the scores so far apart, the losing team had to concede defeat.（由于比分差距太大，输的一方不得不承认失败。）