“在走下坡路”常见的英文表达有：
be on the decline：强调处于一种逐渐衰落、下降的状态。例如：The company's profits have been on the decline for the past few years.（这家公司过去几年的利润一直在走下坡路。）
be going downhill：较为口语化，表达事物正朝着不好的方向发展，情况在变差。例如：Since he lost his job, his life has been going downhill.（自从他丢了工作，他的生活就开始走下坡路了。）
be in a downward spiral：侧重于描述一种不断恶化、陷入恶性循环的下降趋势。例如：The economy of this small town has been in a downward spiral due to the closure of the major factory.（由于主要工厂的关闭，这个小镇的经济一直在走下坡路，陷入恶性循环。）