The thick furred skin was what the hunters were going after for the commercial trade.
那厚厚的毛皮就曾经是捕猎者为了商业贸易所要设法得到东西.
语言点
furred skin ——长着软毛的皮
go after 追求,设法得到; 追捕
what 是关系代词型连接代词,相当于汉语的“所...的”,此处等于 the thing which；what 在此处作 go after 的宾语.what the hunters were going after,可以改写为一个定语从句 the thing which (或者that) the hunters were going afte