波状的起伏

例句：

1. 1. The ocean's waves were crashing against the shore.
   海浪拍打着海岸。
2. 2. The undulating hills are a sight to behold.
   起伏的山丘令人叹为观止。
3. 3. The ripples on the surface of the lake indicate the presence of fish.
   湖面上的涟漪表明有鱼存在。