The problem with this approach is that each country has a different median income, so the definition of what is middle class shifts from place to place.
这种方法的问题在于每个国家的收入中间值不同,所以中产阶级的定义也就随着地域的不同而有所变化。
2
Some 40 years ago, the former Northern Rhodesia was a middle-incomecountry. Average Zambians were wealthy by African standards.