Great changes have taken place since then in the factory _______we are working.为什么是where where是in which 句子中不是we are working in the factory不缺成分吗

Great changes have taken place since liberation Great changes have taken place there. There have been great changes in computers(同义句）Great changes have __ __in computers great changes Great changes Great changes have taken place in my hometown since 1930.请问句子中的Great changes是什么意思? great changes take place since liberation 和 Great changes have taken place since liberation的区别 There have been great changes in Sunshine Town. 同义：Great changes have___ ___in Sunshine Town. there have been great changes为什么用have been Great changes have taken place in Shanghai's transportation.翻译? Great changes have taken place in our city r____ Great changes have taken place in our hometown的翻译 Great changes have taken place in my hometown _____ (recent). great changes have taken place there there 怎么放在后面 There have been great changes,so everything looks s__ here there have been great changes in computers什么意思 there have been great changes in my hometown_________(resent) great changes have taken place over the past fifty years.