gentle undulation 轻微的起伏
undulation of the hills 山峦的起伏
rhythmic undulation 有节奏的波动
A: The landscape here has a beautiful undulation.
A：这里的地貌有着美丽的起伏。
B: I agree, the way the hills rise and fall is very scenic.
B：我同意，这些山丘起伏的样子非常有景色。
1) 波动，波动运动
2) 起伏，波浪状形状
3) 涟漪，波纹
1. 波动，起伏
noun
1. A rising and falling motion or a wavy shape.
Synonym: wave, ripple, swell