磨杵成針

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

to rub / to grind / to polish / to sharpen / to wear down / to die out / to waste time / to pester / to insist

grindstone / to grind / to turn round

pestle / to poke

surname Cheng

to succeed / to finish / to complete / to accomplish / to become / to turn into / to be all right / OK! / one tenth

needle / pin / injection / stitch / CL:根[gen1],支[zhi1]