すりつぶす, 挽く
reduce (something) to small particles or powder by crushing it
きしむ, すり合わせる
rub (something) together or against something else with a harsh, grating sound
骨を折る, 猛勉強する
perform a repetitive or tedious task
単調な仕事, 骨の折れる仕事
a repetitive or tedious task or period of work
挽くこと, きしみ音
the action or sound of grinding