Story 7-look at the sky from the bottom of a well(坐井观天）

There is a frog. He lives in a well and he never goes out of the well. He thinks the sky is as big as the mouth of the well.
One day, a crow comes to the well. He sees the frog and says:"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 and says:"The sky is only as big as the mouth of the well. How do you fly from the sky?"
The crow says:"The sky is very big. You always stay in the well, so you don't know the world is big."
The frog says:"I don't believe."
But the crow says:"You can come out and have a look by yourself."
So the frog comes out from the well. He is very surprised. How big the world is!