磨杵成针

to grind one's way through an ink stone; to persevere in a difficult task (idiom)

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 assiduously and tirelessly (idiom); see also 头悬梁，锥刺股

to study diligently; to train assiduously

to study diligently

to chip away at a task and not abandon it (idiom); to chisel away at sth; to persevere