effectiveness
  有效,有力
  effectiveness
  效用; 有效性
  effectiveness
  有效 效用
  Ef·fect·ive·ness, n. The quality of being effective.
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  effectiveness
       n 1: power to be effective; the quality of being able to bring
            about an effect [syn: effectivity, effectualness, effectuality]
            [ant: ineffectiveness]
       2: capacity to produce strong physiological or chemical
          effects; "the toxin's potency"; "the strength of the
          drinks" [syn: potency, strength]