磨穿鐵硯 [ㄇㄛˊ ㄔㄨㄢ ㄊㄧㄝˇ ㄧㄢˋ; mo2 chuan1 tie3 yan4] to grind one's way through an ink stone to persevere in a difficult task (idiom) to study diligently (idiom) ◄ ►