outer stay

例句：

1. 1.The outer shell of the ship is made of steel.
   船的外壳是用钢制成的。
2. 2.The outer shell of the building is made of glass.
   这座建筑的外壳是用玻璃制成的。
3. 3.The outer shell of the car is made of plastic.
   这辆车的外壳是用塑料制成的。