The passage talks about the author's thoughts of the film The Time Machine. If he could, the author would go back to the Berlin Olympics, where Jessie Owens won four gold medals, showing how wrong Hitler's ideas were.
It's an exciting idea to have had such a time machine to witness the past events and even try to make a difference. If I had a chance to go back in time, I would choose 1990's. I would travel around China to learn more about what was happening in that period. I would ask the ordinary people what they thought about the country's future. I would see what the nature environment and the social situation were like. I would also track my parents' life, where they should be plenty of happiness.
If I achieved all these above, I would have a better understanding of the development of China in the past 30 years. Thus, I would know what's the right thing to do in the future, cherishing the age I am in and creating a better life.
P.S. the example of the starting:
The author introduces the film "The Time Machine", in which the hero invents a time travelling machine to save his sweetheart. He also imagines where he would go if he could travel through time.