An old gentleman whose eyesight (视力) was falling came to stay in a hotel room with a bottle of wine (酒) in each hand. On the wall there was a fly which he took for a nail (钉子). So as soon as he hung them on, the bottles fell broken and the wine split all over the floor.
When a waitress discovered what had happened, she felt really sorry for him and wanted to give him a hand.
So the next morning when he was out taking a walk in the garden, she put a nail on the wall exactly where the fly had stayed.
Now the old man entered his room. The smell of the split wine reminded him of the accident. When he looked up at the wall, he found the fly was there again! He walked to it carefully and hit it with all his strength.
On hearing a loud cry, the waitress rushed in. To her great surprise, the poor man was there sitting on the floor, his face was pale and a lot of blood was running on his right hand.
