Economic exchange was clearly very important as the Roman army brought with it very substantial spending power.
随着罗马军队带来了巨大的购买力，经济交流显然是非常重要的。
2
These incomes are converted not at market exchange rates, but at purchasing-power parities (PPPs), taking account of the higher cost of living in Japan.
这些收入不是按照市场汇率换算的，而是按照平均购买力计算的，把在日本更高的生活成本考虑了进去。
3
It is based on the theory of purchasing-power parity (PPP), which says that exchange rates should equalise the price of a basket of goods in each country.