The thing is, though, that we've been building on the mental achievements of those that came before us for so long that it's easy to forget that certain abilities haven't already existed.
然而，我们所倚赖的前人思想成就 有着太过久远的历史， 以至于我们忘记这些能力并非与生俱来。 在研究人类历史的过程中，