bottom ice

例句：

1. 1.The ice on the bottom of the lake is thick enough to support a small boat.
   湖底的冰足够厚，可以支撑一艘小船。
2. 2.The ice was so thick that it was almost impossible to walk across.
   冰太厚了，几乎无法行走。
3. 3. They used to skate on the bottom ice during winter.
   他们过去在冬天会滑冰在底部冰上。