Great changes have taken place since you left.这句话是个什么从句?省略了什么关系连词?省略的关系连词加在哪?

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.