bottom shell

例句：

1. 1. The car's bottom shell was dented by the impact.
   汽车的底部壳体因为撞击而凹陷。
2. 2. The scientist found a new way to make the bottom shell of the spacecraft lighter.
   科学家发现了一种使太空船底部壳体更轻的新方法。
3. 3. The bottom shell of the ship is made of strong, durable materials.
   这艘船的底部壳体由坚固耐用的材料制成。