问题
Great changes __ in the city in the past 20 years, anda lot of factories ____.
A:have beentaken place; have been set up
B:have takenplace; have set up
C:have takenplace; have been set up
D:were takenplace; were set up
B:have takenplace; have set up
C:have takenplace; have been set up
D:were takenplace; were set up
正确答案是：
