In the last twenty years, seven Canadian scientists _____ th

In the last twenty years great c___have taken place in China 英语翻译Over the last 30 years ,social scientists have conducted 英语翻译Over the last 30 years,social scientists have conducted Gteat changea_____(happen)in china in last twenty years. _____ in beijing for more than twenty years , he knows the c in the last few years scientists should be kept___of the latest developments in th In the past few years, Chinese scientists ________ great suc During the discussion in the meeting,the scientists _____ so When I was twenty-seven years old, I was a clerk in San Fran over the past twenty years 还是in the past twenty years The judge（ ）the murderer to twenty years in prison.