问题
Great changes ___ in the city, and a lot of factories ___
A:have been taken place, have been set up
B:have taken place, have been set up
C:have taken place, have set up
D:were taken place, were set up
B:have taken place, have been set up
C:have taken place, have set up
D:were taken place, were set up
正确答案是：
