Undulations
(undulation 的复数) n. 波动, 波状弯曲, 起伏\\n[医] 波动
🗣️ 情景例句
Don't let me interrupt you.
别让我打搅你们。
He that falls today may be up again tomorrow.
今天跌倒的人也许明天会站起来。
Yes, it helped me out a lot.
嗯，收获不少，