In the past four decades, China has experienced several economic and social changes, their economy has developed and basically boomed, especially since the early XXI century. An example of this is their "reform and opening up" policy, starting in the late 70's, they decollectivized their agriculture and opened the country to foreing investment.
The country has experienced some social change as well, due to the prosperity the economy has brought, but compared to the economic changes, the social change has been small. Chinese society still has serious issues like information censorship, human rights violations or lack of enviromental care.
After Japan attacked Perl harbor Americans put Japanese citizens from USA to concentration camps and took away their rights because they thought there were spies on Japan but in the end there wasn’t a spy and when they were released from the camps they had nowhere to go.
Global warming is a big factor of extinction and will continue for years
Maybe a pep rally, to bring people together and for each grade's students to be a team and get along, and to also have fun . A pep rally can be used as a rally to bring people to get along and together.