VERB
波动；起伏；摇曳
Something that undulates has gentle curves or slopes, or moves gently and slowly up and down or from side to side in an attractive manner.
例句
As we travel south, the countryside begins to undulate as the rolling hills sweep down to the riverbanks...
我们一路南行，乡间开始变得起伏不平，绵延的山峦一直延伸到河岸。
His body slowly undulated in time to the music.
他的身体随着音乐的节拍慢慢摆动。