self-pos·ses·sion /-pəˈzɛʃən ||ˈsɛ-/
  沈著,冷靜
  Self-pos·ses·sion n. The possession of one's powers; calmness; self-command; presence of mind; composure.
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  self-possession
       n : the trait of resolutely controlling your own behavior [syn:
           self-control, possession, willpower, self-command,
            self-will]