短语词组短语undulate fold 波状褶皱undulate quantity 脉动值undulate embelia 平叶酸藤子undulate shape 起伏形态to undulate 荡漾undulate equation 波动方程Paphia undulate 波纹巴非蛤Undulate e 波动undulate forming 起伏成形 返回 undulate