坚硬的外皮；贝类的壳；物体的硬壳husk; shell; casing

• 蛋壳

  egg shell

• 胡桃壳

  walnut shell

• 谷壳

  husk

• 葵花子壳

  sunflower-seed husk

• 西瓜子壳

  watermelon-seed husk

• 蜗牛壳

  snail shell

• 炮弹壳

  artillery shell

• 子弹壳

  spent cartridge

• 热水瓶壳

  thermos flask casing

• 表壳

  watchcase