There is a frog. He lives in a well (井) and never comes out. He thinks the sky is only as big as the mouth of the well. One day a crow (乌鸦)comes to the well. He sees the frog and says, “Hey frog, let's have a talk." Then the frog asks, “Where are you from?" I fly from the sky, the crow says. The frog feels surprised (惊讶) and says, “The sky is only as big as the mouth of the well. How can you fly from the sky?" The crow says, “The sky is very big. You stay in the well, so you don't know how big the world (世界) really is." The frog says, “I don't believe (相信) you." But the crow says, “You can come out and have a look for yourself."
So the frog comes out from the well and is surprised at how big the world is!