translation.en: We know a little bit more today than we used to know, but we still know too little, and certainly there are many different processes — economic, social, political — that need to be studied more.
translation.zh: 相比以前，现今我们对这个问题 了解的更多了，但是我们还是知之甚少， 另外，还应该在相关的不同领域， 例如经济，社会，政治等 投入更多的研究。