这句话可以有四种提问法,分别对于主语,谓语,地点状语,时间状语状语
对主语they提问,用：Who went to the farm last october?
对谓语went ,用：What did they do last october?
对地点状语the farm提问,用Where did they went to last october?
对时间状语last october提问,用When did they went to the farm