目前面临的四个问题，水，空气，粮食，适婚男过剩

https://www.youtube.com/watch?v=eXsV4IGSnSo

https://www.youtube.com/watch?v=t9qoacd5eaM

https://www.youtube.com/watch?v=XAkd3fXZo78

https://www.youtube.com/watch?v=jJmaveBCpoo