un·known /-ˈnon/
 (a.)未知的,陌生的未知的東西,未知數
 unknown
 未知
 Un·known a. Not known; not apprehended. -- Un*known*ness, n. [R.]
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 unknown
      adj 1: not known; "an unknown amount"; "an unknown island"; "an
             unknown writer"; "an unknown source" [ant: known]
      2: being or having an unknown or unnamed source; "a poem by an
         unknown author"; "corporations responsible to nameless
         owners"; "an unnamed donor" [syn: nameless, unidentified,
          unnamed]
      3: not known to exist; "things obscurely felt surged up from
         unsuspected depths in her"- Edith Wharton
      4: not famous or acclaimed; "an obscure family"; "unsung heroes
         of the war" [syn: obscure, unsung]
      5: not known before; "used many strange words"; "saw many
         strange faces in the crowd"; "don't let anyone unknown
         into the house" [syn: strange]
      n 1: an unknown and unexplored region; "they came like angels out
           the unknown" [syn: unknown region, terra incognita]
      2: anyone who does not belong in the environment in which they
         are found [syn: stranger, alien]
      3: a variable whose values are solutions of an equation [syn: unknown
         quantity]