Many times, people are too persistent and struggle for the result of a process. However, after getting the result, they felt guilty. I think thousands of years of history have turned into clouds, leaving only a few thick ancient books. Many things, such as selling cigarettes, wars and disasters, are all because of the selfishness and greed of a few people. There are many things that are not needed. Since we can't change history, when we write today, we should not fail to understand the facts of many times and many things, and we should not make much ado about nothing.