undulation
n
(a) [U] wave-like movement or appearance 波动; 起伏.
(b) [C] one of a number of wave-like curves or slopes 波状的弯曲或斜坡
The downs fell in gentle undulations to the sea. 这块丘陵地略带倾斜伸向大海.
🗣️ 情景例句
I think aerobics is easy.
我觉得有氧运动很容易。
If it doesn't rain tomorrow, will you get a haircut?