These videos could help us investigate the visual signs of the crackdown.

这些视频可以帮助我们调查镇压的视觉迹象。

No visual signs of trauma. No ligature marks.

没有明显的外伤 没有绑痕。

On even the most recent hypothesis, humans spent 45,000 years talking before it occurred to a few to make their words into durable visual signs.

即使是根据最新的假设，人类也花了 45,000 年的时间进行交谈，然后才让少数人想到将他们的话语变成持久的视觉符号。