We're dealing with probably the biggest missing link in what we know about human evolution.

我们正在解决的可能是我们所知的人类进化过程中缺失最大的一环。

As scientists look deeper into our genes, they are finding examples of human evolution in just the past few thousand years.

随着科学家们对我们的基因进行更深入的研究，他们在过去的几千年里就发现了人类进化的例子。

But crying as an expression of feeling is unique to humans and has played an essential role in human evolution and the development of human cultures.

但哭泣作为一种情感的表达是人类独有的，这在人类进化和人类文化的发展中发挥了重要的作用。

Did parasites drive human evolution?

寄生虫催使人类进化？

Studying human evolution directly is obviously impossible.

直接研究人类的进化是明显不可能的。