Let's-Read-and-Find-Out Science: A Nest Full of Eggs 自然科学启蒙-一窝鸟蛋

  A baby bird is growing inside an egg. Slowly the bird develops, until one day it cracks through the shell. Safe inside the nest, under the care of its parents, the chick grows stronger. Soon it will learn how to fly and take care of itself. By next spring it will be ready to build its own nest and raise chicks of its own.