about-face /əˈbaʊtˈfes/ 名詞
  向後轉, 作大改變
  about-face
       n 1: act of pivoting 180 degrees, especially in a military
            formation [syn: about turn]
       2: a reversal in attitude or principle or point of view; "an
          about-face on foreign policy" [syn: volte-face, reversal,
           policy change]
       v 1: turn, usually 180 degrees
       2: change one's mind and assume the opposite viewpoint