参考答案：当今的世界比历史上任何一个时期都要不平等。这有其基本原因：200年前，每个人都很穷。经济发展只是相当近来的一段时期(发生)的事，但这却是经济状况出现极大分化的时期。世界上相对很小的一部分地区达到了经济学家称为现代经济发展/增长水平，而且他们在人均收入方面，年年持续增长。如果你将两个世纪以来的增长累计，那将是个相当大的变化，从物质条件来衡量，(生活水平的)增长也许是20倍或更多。

解析：[听力原文]
The world is more unequal than at any time in world history. There’s a basic reason for that: 200 years ago everybody was poor. The period of economic growth is a fairly recent period, but it’s been a period of extreme differentiation in economic performance. A relatively small part of the world achieved what the economists call a modern economic growth. And they sustained the increase year after year, in income per person. When you accumulate that over two centuries, you get quite a change, maybe a twenty-fold increase or more in the standard of living measured in material terms.