Early in the morning, the big tree in front of the door is full of birds returning from travel, and they are exchanging experiences along the way. Wearing a black dress and a small tail like scissors, you will see them busy in spring. They fly around in the sky with dirt and grass in their mouths, and use these materials to build their own happy nests. They build their nests under the eaves, which seems to show that they trust human beings very much and believe that human beings will not steal eggs and catch chicks. After the nest was built, the swallows began to lay eggs and hatch. During this period, Yan's father took the initiative to be Yan's mother's nanny. During the day, Yan's father flies out to find food for Yan's mother. In the evening, Yan's father became a security guard again, standing beside the Bird's Nest to keep vigil for Yan's mother. After several weeks of unremitting efforts, the swallow finally hatched. They are naked, bulging, and their mouths are chirping in their nests. They look ugly. Yan's mother brought a bug, and they all came for it. A few weeks passed, and the swallows began to grow feathers, so they began to be restless. They walked slowly to the nest, spread their featherless wings and flew out to see the beautiful world outside, but they were too young to master the flying skills, so they failed to realize their wishes every time. A few weeks later, the swallow's feathers were full, so Mother Yan began to teach the swallow how to fly. Swallows and geese jump from their nests to the roof together. The goose demonstrated the author's action essentials in front, and the swallow followed. Maybe the swallow is too eager to fly, so she learns quickly. Mother Yan began to let the swallows really fly. Mother Yan directs the swallows like a coach. Swallows were photographed in a neat and orderly row and rushed forward to spread their wings. Ah! Swallows flew, and they finally realized their dreams. When autumn comes, the little swallows will fly to a warm place with their parents and come back in spring to breed in this beautiful city. How cute these little animals are! They use mud and grass to build nests, lay eggs and hatch, then the chicks chirp, and finally the swallows learn to fly. What a happy process!