參考詞匯：垃圾分類 trash sorting
Having learned that you are interested in the trash-sorting program promoted recently in China, I am here writing to give you a brief introduction.
As far as I know, Shanghai has become the pioneer of our country's waste sorting policy. As of July 1st this year, the residents in Shanghai have not been able to dump their waste bags in whichever bin was closest. On the contrary, domestic waste is required to be classified into four categories: dry refuse, wet trash, recyclable waste and hazardous(dangerous) waste.
Faced with the new rule, many citizens in Shanghai are finding it a little too complicated, with every item of waste now under careful scrutiny(examination) and classification. Still, there are more people who warmly support the policy because it helps people to cultivate greener lifestyle habits and helps China to become a more beautiful country.
As we all know , the time of 5G technology is coming , it is called the fourth industrial revolution , future of computer science lies in the artificial intelligence，it is the research and artificial simulation of human thought and eventually be able to make a human like to think the same machine , for human services and to help people solve problems.
After all, people thought it was unique, there are feelings, there are a variety of character, this will be very difficult to achieve in the machine.In fact, to do the same as the human thinking machine, the only one of the artificial intelligence, is by no means all. Through the study of artificial intelligence, it can resolve all kinds of scientific problems, promote the development of other science will have a great impact on all people's lives .
I believe that the science of artificial intelligence is waiting for humanity to explore it step by step .3、疫情感謝信
參考詞匯：流行病epidemic 疫情 epidemic situation 新型冠狀病毒 novel coronavirus
Dear Medical workers，
I am Li Hua,a high middle school student in Shanxi. I'm writing to express sincere gratitude to you all for your devotion and sacrifice in this battle against the Novel Coronavirus.
In this epidemic, it is you who, despite the lack of equipment and the potential of infection, desperately rescue those infected but striving for life. It is also you who have shed new light on the virus with expertise to build up our confidence to defeat it. It is you who deserve all the admiration and love!
I can never express our thankfulness too much for your selfless contribution. It's widely believed that our joint efforts China will win the battle and make a quick recovery.
Good luck and stay well!
One possible version：