地形起伏

例句：

1. 1. The mountain range is characterized by its steep slopes and rugged terrain.
   这座山脉以其陡峭的坡度和崎岖的地形而闻名。
2. 2. The valley's shape is determined by the terrain around it.
   山谷的形状由周围的地形决定。
3. 3. The river flows through a landscape of rolling hills and gently undulating terrain.
   这条河流流经一片丘陵起伏、地势平缓的景观。