Question

There __________ great changes in our hometown over the twenty years.

1. A.
   have taken place
2. B.
   have had
3. C.
   have been
4. D.
   were

Answer 1

C
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。