I am a Chinese, I must claim I don't know why this paper can be published in Science because its method is totally wrong. I think most of the Chinese citizens even don't have email addresses and they just use phone call and Wechat. There are 8 people in my family but just I have sent emails before. They even never ever sent an email before and they don't know how to use it! I know how the Western media has smeared China, but I did not know that the academic has begun. It really makes me sad. If authors go back to the place they put the wallets, they are likely to find that the wallet has been taken care of or in the lost and found box. By the way, welcome to China, I know there will be some places not good but it's better to know China with your eyes and thoughts.