Ask how clear the canal is because there is running water at the source.

Zhu's reading thoughts.

Original: When the square pond of half an acre is opened, the sky is high and the clouds are light. Why is the water in the pond so clear? Because there is inexhaustible living water for it.

A half-acre square pond is displayed like a mirror, in which the brilliance of the sky and the shadow of floating clouds move together. Why is the water in that square pond so clear? It is because there is an inexhaustible source to continuously transport living water for it.