go bad
  變環
  go bad
       v 1: stop operating or functioning; "The engine finally went";
            "The car died on the road"; "The bus we travelled in
            broke down on the way to town"; "The coffee maker
            broke"; "The engine failed on the way to town"; "her
            eyesight went after the accident" [syn: fail, give
            way, die, give out, conk out, go, break, break
            down]
       2: become unfit for consumption or use; "the meat must be eaten
          before it spoils" [syn: spoil]