sand-gravel surface

例句：

1. 1. The beach is covered with sand-gravel surface during the summer.
   夏天海滩上铺满了沙砾表面。
2. 2.The construction crew was working on a sand-gravel surface road.
   施工队正在铺设一条沙砾表面道路。
3. 3.The engineer inspected the sand-gravel surface for any signs of wear and tear.
   工程师检查了沙砾表面，看是否有磨损的迹象。