On a farm lived a father and a son. The father always got up early and read by the window. One morning, the son came up to him and said, Dad, I read books at night but forget most of them the next morning. What's the good of reading?
The father didn't reply to his question at once. He passed him a basket that was used to carry coal (煤). He said, "Get some water from the river with the basket and then I'll tell you the answer."
The son felt surprised but he did as his father said. He tried many times but every time the water leaked(漏掉) from the basket.
An hour later, the son came back with the empty basket and told his father it was impossible to hold water with the basket. The father said with a smile, "Yes, you are right, my son. The basket can't hold water. But did you notice the basket was different?" The son found the dirty basket had become clean. The father continued, "Reading is like holding water with the basket. Although we can't remember all we read, we have changed while reading."