solid borne sound

例句：

1. 1. The solid rock is difficult to move.
   这块坚硬的岩石很难移动。
2. 2. The solid structure of the building is impressive.
   这栋建筑的坚固结构令人印象深刻。
3. 3. The solid gold bars are worth a fortune.
   这些纯金条价值连城。