ㄇㄛˊㄔㄨˇchǔㄔㄥˊchéngㄓㄣzhēn

  1. 比喻只要有恆努力無論多麼困難可以成功參見鐵杵磨成針

to grind an iron bar down to a fine needle (idiom)​; fig. to persevere in a difficult task, to study diligently