Owing to the open ---door policy,great changes have taken pl

Owing to the open ---door policy,great changes have taken pl great changes have taken place over the past fifty years. great changes have taken place in the village ____the years "Great changes have taken place in China since the introduct Great changes have taken place there. Great changes have taken place there Great changes have taken place since liberation Great changes have taken place ...in china Great changes have taken place in China. I have to ____ the door open After China adopted the open-door policy,we have more and mo Great changes?the last three years.A.have taken place B.have