?As everyone knows, the way of farming has changed a lot.

?Of course. And some other changes ________ on the farms in the last 100 years.

A. takes place

B. have taken place

C. took place

D. have been taken place

--As everyone knows, the way farming has changed a lot.

--Of course. And some other changes ________ on the farms in the last 50 years.

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