sem·pi·ter·nal /ˌsɛmpɪˈtɚ/
  (a.)永久的,永恆的
  Sem·pi·ter·nal a.
  1. Of neverending duration; everlasting; endless; having beginning, but no end.
  2. Without beginning or end; eternal.
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  sempiternal
       adj : having no known beginning and presumably no end; "the
             dateless rise and fall of the tides"; "time is
             endless"; "sempiternal truth" [syn: dateless, endless]