1 to torment

2 to torture

1 research

2 a study

3 classifier: 项 xiàng

4 to research

5 to look into

1 mill

1 polish

2 grind

1 to wear down

2 to sap

3 to whittle away

4 to while away

5 to idle away

1 a blade will get rusty if it is not sharpened; a man will fall behind if he doesn't study (idiom)

1 lit. cutting and polishing (idiom)

2 fig. to learn by exchanging ideas or experiences

1 lit. to kill the donkey when the grinding is done (idiom)

2 to get rid of sb once he has ceased to be useful

1 If you work at it hard enough, you can grind an iron bar into a needle.

2 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

3 to study diligently

1 the road to happiness is strewn with setbacks (idiom)