self-act·ing /-ˈæktɪŋ/
 (a.)自動的
 Self-act·ing a. Acting of or by one's self or by itself; -- said especially of a machine or mechanism which is made to perform of or for itself what is usually done by human agency; automatic; as, a self-acting feed apparatus; a self-acting mule; a self-acting press.
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 self-acting
      adj : designed to activate or move or regulate itself; "a
            self-activating sprinkler system" [syn: self-activating,
             self-moving, self-regulating]