great changes ---in china since the people's * ---in 1949
问题描述：
great changes ---in china since the people's * ---in 1949
A.have taken place;was founded
B.has taken place ;was founded
C.have been taken place;founded
D.took place;founded
答
选择 A
首先,take place "发生”--这个短语没有被动语态,这要记住!因此排除了C
since是完成时态的标志,排除了D
又因为句子的主语是个复数,所以用have,排除了B
另外,还得记住 since后面的从句常用 一般过去式