While in America the trend started as a reaction to the economic decline——after the mass redundancies caused by downsize in the late’80s——and is still linked to the politics of thrift, in Britain, at least among the middle-class downshifters of my acquaintance, we have different reasons for seeking to simplify our lives.
请问老师,这里的while引导的是让步状语从句还是并列句。