a hard case

例句：

1. 1.The box is made of a hard case.
   这个盒子是用硬壳做的。
2. 2.The bird's hard case protects its eggs.
   鸟的硬壳保护着它的蛋。
3. 3.The car was scratched by a hard case.
   汽车被硬壳刮伤了。