The way in which men produce their means of subsistence depends first of all on the nature of the actual means they find in existence and have to reproduce.

解释：情绪变化会影响身体生理反应，如贪心时口水增多，悲哀时流泪，体现了情绪与健康的关联。

The most important tool of the architect is empathy.

The most exciting aspect of chemistry is the ability to create new molecules that have never existed before.