ef·fi·ca·cious /ˌɛfəˈkeʃəs/
  (a.)有效的,靈驗的
  Ef·fi·ca·cious a.  Possessing the quality of being effective; productive of, or powerful to produce, the effect intended; as, an efficacious law.
  Syn: -- See Effectual.
  -- Ef*fi*ca*cious*ly, adv.
  ◄ ►
  efficacious
       adj 1: marked by qualities giving the power to produce an intended
              effect; "written propaganda is less efficacious than
              the habits and prejudices...of the readers"-Aldous
              Huxley; "the medicine is efficacious in stopping a
              cough" [ant: inefficacious]
       2: producing or capable of producing an intended result or
          having a striking effect; "an air-cooled motor was more
          effective than a witch's broomstick for rapid
          long-distance transportation"-LewisMumford; "effective
          teaching methods"; "effective steps toward peace"; "made
          an effective entrance"; "his complaint proved to be
          effectual in bringing action"; "an efficacious law" [syn:
          effective, effectual] [ant: ineffective]