毛毛虫变蝴蝶， 身体里发生了什么？

A caterpillar eats and eats all day. 毛毛虫一天到晚吃个不停。 Then it hides inside a hard shell. 然后它躲进一个硬壳里。 This stage is called a pupa. 这个阶段叫蛹。 Inside, the old body almost melts away. 壳里，旧身体几乎融化成汤。 From that soup, a new body grows. 就靠这锅汤，长出新的身体。 Wings and legs form little by little. 翅膀和腿一点点长出来。 Finally a beautiful butterfly comes out. 最后，一只漂亮的蝴蝶飞了出来。