请教一个句子成份的问题When economic forces are unfettered,Americans bel

请教一个句子成份的问题
When economic forces are unfettered,Americans believe,supply and demand determine the prices of goods and services.Prices,in turn,tell businesses what to produce； if people want more of a particular goods than the economy is producing,the price of the goods rises.【That catches the attention of new or other companies that,sensing an opportunity to earn profits,start producing more of that goods.】
现在分词短语 sensing an opportunity to earn profits 应该是作定语从句 that start producing more of that goods 的原因状语,