I get tired so easily these days.我最近总是感到乏力。That means you"re over the hill.那是因为你在走下坡路。Now, he is over the hill.现在，他在走下坡路。over the hill走下坡路If I"m too old to cut the mustard, maybe I should retire.如果年纪大了不能胜任，我可能就会隐退Cut the mustard胜任He can"t cut his mustard.他不能很好地完成分内工作。If he can"t cut the mustard, we"ll have to find someone else to do the job.如果他没能力完成自己的工作，我们会找他人来做。
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