run out of steam
失去动力或能量，力不从心
口语·描述疲惫无力
英文释义
to lose energy, motivation, or momentum; to tire or exhaust
例句
After three hours of studying, I ran out of steam.
典故来源
源自蒸汽机燃料耗尽停止运转，比喻人失去能量或动力。