Man is faced with more and more problems which threaten man's existence on Earth.The resources will soon be exhausted.  Many diseases can't be cured.  And the problems of pollution and population are also getting worse according to some studies.

人类正面临着越来越多的问题，这些问题威胁着人类的生存。资源将很快被用完，许多疾病还不能治愈，研究表明，污染问题和人口问题正在变得越来越严重。