back across over

In these programmes, I'm travelling back in time and across the globe, to see how we humans, over two million years, have shaped our world, and been shaped by it.

在这些节目里，我将穿梭时空，跨越世界，去看看我们人类在这两百万年时光中，是如何改变世界，又是如何被世界改变着。

You will rarely come across something that has not been struggled over and solved back in 2004.

很少会遇到在2004年出现并且没有解决的问题。

Over three hundred of them are scattered across Costa Rica, but we’ll never know why – the people who made them back in 1,000 C.E. are long gone and had no written records.

超过300个石球零散分布在哥斯达黎加，我们对它们的来历一无所知——人们在公元1000年时将它们弄回来的事迹已无从考究。