A Lion was awakened from sleep by a Mouse running over his face. Rising up angrily, he caught him and was about to kill him, when the Mouse piteously entreated, saying: "If you would only spare my life, I would be sure to repay your kindness." The Lion laughed and let him go. It happened shortly after this that the Lion was caught by some hunters, who bound him by strong ropes to the ground. The Mouse, recognizing his roar, came and gnawed the rope with his teeth and set him free, exclaiming:
"You ridiculed the idea of my ever being able to help you, expecting to receive from me any repayment of your favor; now you know that it is possible for even a Mouse to con benefits on a Lion."
Once upon a time, a gigantic fish named Kun lived in the North Sea. No one knew how large it actually was. This fish could change itself into Peng （a roc）， a huge bird measuring thousands of kilometers in length. When the bird spread its wings, it looked like huge clouds in the sky. It could, in one stretch, fly from the North Sea to the South Sea on the other side of the globe, and soar up to 45,000 kilometers ?in the heaven.
The bird can surely fly over a long distance without stopping. Now people use this idiom to wish others have a successful career or a bright future.