Under the eaves, the swallow's mother said to the swallow, "Go to the vegetable garden and see what's the difference between winter melon and eggplant?" The swallow went and came back and said, "mom, mom, the wax gourd is big and the eggplant is small!" " "
Mother Swallow said, "You are right. Can you go and see the difference? " The swallow went again and came back and said, "mom, mom, the wax gourd is green and the eggplant is purple!" " "
Mother Swallow nodded and said, "Very good. However, can you take a closer look and see what's the difference between them? " The swallow went again and came back happily and said, "Mom, mom, I found fine hairs on the skin of wax gourd and small thorns on the handle of eggplant!" " "Mother Swallow smiled and said," You are making progress every time! " "