首先更正一个错误,定语从句中,where 在从句中不能作主语或宾语,只能作状语 先行词为地点名词,要看后面的从句所缺的成分,来确定先行词 如 This is the factory which/that I once worked in.(worked in 后面缺宾语,故用关系词which/that ) This is the factory where I once worked.(从句 I once worked 不缺主语和宾语)
that 作主语或宾语可以；where不可以吧，它应该是状语。 如，I spent 10 days at the farm that was owned by my uncle. 这句话，that是从句的主语。 I spent 10 days at the farm where my uncle lived. 这里，where就是个地点状语。
