The origin of this slang can be traced back to the story in ancient legends in China. In the Tang Dynasty, a businessman named Wang Sungui met a fairy on his journey and asked him how to make more money. The fairy told him, "you will get a lot of treasure and gold in the future." Take care of it on your way home. " So Wang Sungui put the treasure in a big bag and began to return to his hometown. Soon after, Wang Sungui passed a river and needed to cross it. As there was no bridge or boat available at that time, I decided to swim across the river with my big bag on my back. However, due to the rapid current and heavy luggage, he could not cross the river smoothly and eventually fell into the water. After a painful struggle, I finally climbed out of the water and found that the "big bag" full of priceless treasures was gone. Since then, it has become a fable to describe someone who has lost a rare opportunity or advantage. The loss was caused by his negligence, carelessness or carelessness.