2．Great changes ______ in China in the past 20 years.

Great changes _________ in China in the last two decades.

1. A.
   have taken place
2. B.
   took place
3. C.
   have been taken place
4. D.
   are taking place

________, great changes ________ in China.

1. A.
   In 1990's, have been taken place
2. B.
   In the 1990s', have been taken place
3. C.
   In the 1990s, have taken place
4. D.
   In 1990s, have taken place

Great changes _________ in China in the last two decades.

A. have taken place                      B. took place       

C. have been taken place                  D. are taking place