zhǐyàogōngfushēn,tiěchǔmóchéngzhēn

Traditional: 只要功夫深，鐵杵磨成針

If you work at it hard enough, you can grind an iron bar into a needle. / cf idiom [[磨杵成針|磨杵成针]], to grind an iron bar down to a fine needle (idiom); fig. to persevere in a difficult task / to study diligently