Question

Decide if each of these sentences should be in the present perfect or past perfect. Then decide if it should be active or passive.
1.Hundreds of Siberian tigers ...(kill) in the last twenty years.
2.After the dinosaurs ...(wipe out), as the result of a catastrophe, mammals were able to flourish.
3.Pandas ...(not see) outside China when Marco Polo arrived there.
4.For centuries before humans arrived, buffalo ...(roam) the American prairies.
5.The number of giraffes in Africa ...(fall) dramatically.

Answer 1

1=killed
2=have wiped out
3=not seen
4=roamed
5=has fallen