一曝十寒 — “To work or study with inconsistent effort”

During the Warring States period, Mencius was critical of King Qi's inconsistent decisions and his susceptibility to the flattery of cunning officials. Mencius told the king, "Even the most vigorous plant cannot survive if you expose it to the sun for one day and then subject it to ten days of cold. Similarly, I spend a short time with Your Majesty, and you might develop a good intention, but as soon as I leave, those sycophants will mislead you again, and you will believe them. What can I do?"

He then used another vivid analogy: "Playing chess might seem like a minor matter, but if you're not fully focused, you won't learn or win. Yi Qiu, the best chess player in the country, taught two apprentices. One was dedicated and followed Yi Qiu's guidance; the other was constantly distracted, imagining a large swan flying by, ready to shoot it with an arrow. Both learned from the same master, but the latter's progress was far inferior. This was not due to a difference in intelligence, but in their level of concentration."

The idiom "一曝十寒" (yī pù shí hán), meaning "one day of exposure to sun, ten days of cold," was later derived from Mencius's plant analogy. It is used to describe someone who lacks perseverance and consistency in their studies or work, being diligent for a short while and then neglecting their efforts for extended periods, thus failing to achieve any significant progress or success.