sand-dune

例句：

1. 1. The sun sets over the vast expanse of sand dunes.
   太阳在广阔的沙丘上落下。
2. 2.The children played on the sand dunes during the summer vacation.
   孩子们在暑假期间在沙丘上玩耍。
3. 3.The sand dunes are a popular destination for tourists seeking adventure.
   沙丘是寻求冒险的游客的热门目的地。