...their food isn't up to standards.( )A.that, ifB.where, ifC...
___producers have to stop production ___their food isn't up to standards为修饰system的定语从句,由于定语从句不缺乏名词性成分,所以先行词system可当做地点看待,故应该使用引导词where或in which引导定语从句,分析该定语从句,___their food isn't up to standards在该定语从句当中作条件状语从句,结合句意,...