to expand and contract in a rhythmic mannerhis heart pitter-pattered with excitement as he waited for the right moment to propose
his heart pitter-pattered with excitement as he waited for the right moment to propose
beat, palpitate, pit-a-pat, pulsate, pulse, throb
fluctuate, oscillate, vibratequiver, tremble
in the 15th century
英语同义词词典收录了63618条英语词条，基本涵盖了全部常用同义词或反义词的辨析及翻译，是英语学习的有利工具。