undulation [ˌʌndʒəˈleɪʃn]

例句:

• The delicious undulation of the lapping water.
  来自R. Church
• She moved with a shorter undulation beside her father's wife.
  她迈着细小飘逸的步子,随着继母走来走去.
  
• The hands at the sides allow for easier body undulation.
  手在体侧时可让身体的波动更容易些.
  
• Would you the undulation of one wave, its trick to me transfer.
  倘若你肯将一个波浪起伏的绝技传授给我.