Let’s take a case study, the last generalized boom-bust cycle in commodity prices, which caused these prices generally to rise (more or less) from some time in the 1960’s until the 1980’s, and then generally to fall until the mid-1990’s. Maybe images matter just as much as substance in explaining that.
我们来进行一个个案研究，最近一次总体性的商品价格繁荣－崩溃周期导致商品价格从20世纪60年代到20世纪80年代普遍上涨（虽然涨幅或大或小），然后开始普遍下跌直到20世纪90年代才结束。或许画面和实质在解释这一现象上同样重要。