介导疼痛的分子非常古老,揭示了这种感觉在进化中的深远根源。
The molecules that mediate pain are ancient, revealing how deeply rooted this sensation is in evolution.
人是会讨价还价的动物:没有其他动物会这样做——没有狗会与另一只狗交换骨头。
There is no escape from the labyrinth of existence.