One evening, grandad said, ‘I once had a friend called day. His first name was Henry, but everyone called him Happy. Happy Day made a very good living. He travelled widely and when he came to a place that he liked, he opened a pet shop and began selling African Ghost Fish.
‘According to Happy, these are the world’s only invisible fish, and they’re especially good pets because they need no food. They live only on water. Once a year, the female Ghost Fish lays eggs. Immediately after that, and if everything is completely quiet, she becomes visible. But in a blink of an eye, she’s gone again. If you see her, you’re extremely fortunate foe she’s the most beautiful creature alive.
‘When Happy told his customers this story, his tanks of fish sold very quickly. When they were completely sold out, Happy usually departed for another town.’
‘Was that because his customers were not satisfied?’ we asked.
‘Not at all,’ grandad said. ‘His customers were completely satisfied. He rarely received a complaint. In fact, many people told him of the pleasure they got from looking at their invisible fish. It was so relaxing. Others enjoyed inviting their friends to see their fish. A few even claimed that they had seen a female Ghost Fish, and that it was truly unforgettable. Yes, Happy was a clever man.’
‘Can you tell us some more about him?’ we said.
‘Not now,’ said grandad. ‘I’m tired, and I want a nap. Why don’t you children go and watch the tank of Ghost Fish in my room? Remember, if you sit quietly and watch really closely, you might even see a female.’
As we rushed excitedly from the room, I heard grandad whisper, ‘Thank you, Happy.’
I wonder what he meant.
从这篇文章中帮我提出一些较高难度的问题、谢谢.