co·in·ci·den·tal /(ˌ)koˌɪn(t)səˈdɛntḷ/
  (a.)一致的,符合的,暗合的
  Co·in·ci·den·tal a. Coincident.
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  coincidental
       adj : occurring or operating at the same time; "a series of
             coincident events" [syn: coincident, coinciding, concurrent,
              cooccurring, simultaneous]