This is the factory where i worked last year.This is the factory which i worked in last year.填什么连接词关键看从句里面缺什么成分,第一句显然缺了一个地点状语,故用where,你的理解是对的.第二句显然缺了一个...This is the factory ()i visited last year为什么填which不填where?因为从句是i visit (the factory) last year.显然从句缺了宾语，而非状语，故用which这么说where不能做宾语，而which既可以做宾语，又可以做状语where 是从句中缺状语时候的连接词，如上面例句中从句缺地点状语。第二个例句之所以使用which是因为这句中的连接词部分有in(in the placein 某个地方，还是宾语)，不是你理解的那样可以做状语连接词，你把in which 整体理解成一个状语连接词（组）