in·con·vert·ible /-ˈvɝtəbəl/
 (a.)不能兌換的,不能變換的
 In·con·vert·i·ble a.  Not convertible; not capable of being transmuted, changed into, or exchanged for, something else; as, one metal is inconvertible into another; bank notes are sometimes inconvertible into specie.
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 inconvertible
      adj 1: used especially of currencies; incapable of being exchanged
             for or replaced by another currency of equal value
             [syn: unconvertible, unexchangeable] [ant: convertible]
      2: not capable of being changed into something else; "the
         alchemists were unable to accept the inconvertible nature
         of elemental metals" [syn: untransmutable]