问题补充：
15. Great changes in the city, and a lot of new buildings .
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
答案：
A. have been taken place; have been set up
(答案→)B. have taken place; have been set up
C. have taken place; have set up
D. were taken place; were set up
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