wear away
  磨損,風化,侵蝕
  wear away
       v 1: cut away in small pieces [syn: whittle away, whittle down]
       2: diminish, as by friction; "Erosion wore away the surface"
          [syn: wear off]
       3: become ground down or deteriorate; "Her confidence eroded"
          [syn: erode, gnaw, gnaw at, eat at]