铁杵磨成针铁杵成针tiě chǔ mó chéng zhēn

an iron pestle can be ground down to a needle—perseverance will prevail; constant dropping wears the stone; little strokes fell great oaks; long,persistent practice makes perfect; with time and patience the leaf of the mulberry becomes satin
❍ ～，是说恒心很重要。Constant dropping wears the stone.It means that perseverance is very essential.

• in number
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• in one way or the other
• in order
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• input
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• inquiry
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