There great changes in our hometown over the twenty years.A. have taken place B. have had

问题补充：

There great changes in our hometown over the twenty years.

A. have taken place

B. have had

C. have been

D. were

答案：

A. have taken place

B. have had

(答案→)C. have been

D. were

解析：由“there”可知，此句应用“there be”句型,排除AB。由时间状语over可知此句时态为现在完成时，故选C。