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 had been to many places 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 don't need any food.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（眨眼）of an eye，she's gone again.If you see her，you're extremely lucky for 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 left for another town. "

"Was that because his customers were not satisfied？" We asked.

"Not at all， "Grandad said. "His customers were completely satisfied.Many people told him that they got great pleasure from their invisible fish.It was so relaxing.A few even claimed that they had seen a female Ghost Fish，and 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（打盹）.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.

阅读材料，根据文中信息帮助 Happy Day 设计一份广告，完成以下任务。

任务 A：补全 1﹣4 题的信息。每空限填一词。任务 B：编写一句广告语，完成第5题。不超过 10 个词。

AFRTCAN GHOST FISH NOW ON SALE At Happy Day's（1） 　 　Shop! • The world's only invisible fish. • They need（2） 　 　food. • The female is the most（3） 　 　creature alive.She becomes visible after she lays eggs. • All customers will be completely satisfied. • The fish will live great（4） 　 　to you. （5）