求这个句子分析，特别是which指代什么？是前面的主语还是后面的宾语

不要担心，看你有英语底子。关系代词顾名思义是一个代词，代替先行词。所以只需看先行词在定语从句中的位置即可明白。用that不用which1）先行词是最高级或他前面有形容词最高级时This is the best --that-- has been used against air pollution in cities.English is the most difficult subject --that-- you will learn during these days.2)先行词是序数词或它前面有一个序数词时He is the last person --that-- i want to see.3)主句中有疑问句Which is the pen --that-- you lost?4)先行词既有人又有物时The bike and its rider --that-- had run over an old man were taken to the police station.5)先行词是 all, much, little ,something,everything,anything,nothing,the one时6）先行词前有 only,any,few,little,no ,all,one of,the same, the very等词装饰时7）有2个定语从句，其中一个关系代词已用which，另一个应用that。Tom built up a factory which produced things that had never been seen before.

就近原则，指代their employeement situation