precursory
  (a.)先驅的,前兆的,作預備的
  pre·cur·so·ry /prɪˈkɝsərɪ/ 形容詞
  預兆的,前驅的
  Pre·cur·so·ry a.  Preceding as a precursor or harbinger; indicating something to follow; as, precursory symptoms of a fever.
  Pre·cur·so·ry, n. An introduction. [Obs.]
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  precursory
       adj : warning of future misfortune [syn: premonitory]