In the ancient world, it was probably rare to castrate a dog or cat.

古时候可能很少阉割猫或狗。

It is difficult for us to imagine what life was like for slaves in the ancient world.

我们很难想象古代奴隶的生活是怎么样的。

I better say something about oil in the ancient world, so that you get a grip on what's going on here.

我最好讲讲古代的石油，这样你们就能了解这里发生了什么。

The ancient world is just not like our world.

古代世界和我们的世界不一样。

That's actually not unusual in the ancient world.

这实际上在古代并非不常见。