cycling
  騎腳踏車兜風,騎腳踏車消遣
  cycling
  循環 週期
  Cy·cle v. i. [imp. & p. p. Cycled. p. pr. & vb. n. Cycling ]
  1. To pass through a cycle2 of changes; to recur in cycles.
  2. To ride a bicycle, tricycle, or other form of cycle.
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  Cy·cling n.  The act, art, or practice, of riding a cycle, esp. a bicycle or tricycle.
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  cycling
       n : the sport of traveling on a bicycle or motorcycle