题干
2．Great changes ______ in China in the past 20 years.
A：took place
B：have taken place
C：were taken place
D：have been taken place
答案(点此获取答案解析）
B
A：took place
B：have taken place
C：were taken place
D：have been taken place
中，
，
，
，则
和
所成的角是（ ）