Some of the challenges that you see here I mentioned before, so there are problems with drought, with pests, with temperature changes and the like.

我之前提到的,你们所见的这些挑战,如干旱问题,虫害问题以及温度变化之类的

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

That explains, in large part, why there was such a decline in population, why the Dark Ages were so dark, lots of poverty, lots of starvation, but also, as I suggested when I spoke of this earlier, also the freedom if you could make it, to learn and also to grow stronger.

这解释了,在绝大部分地区,为什么存在着这一类的人口消减,为什么黑暗时代如此黑暗,如此贫困,如此多的饥荒,但是同时,就如在我之前所提到的,同样可以,如果做得到的话,去学习以及使自身强大

耶鲁公开课 - 古希腊历史简介课程节选