1. (2022九上·法库期末) 阅读图文，然后根据内容回答所提问题。

1. （1） What is the old man's next talk about?
3. （2） How did the old man have got an idea?
5. （3） What time can people float in the air on that day?
7. （4） Why will the gravity of the Earth reduce?
9. （5） Did the old man succeed in playing a joke on people?