1. Harry ate six shrimp at dinner. (= ACTIVE)         
Six shrimp were eaten by Harry at dinner.
2. Beautiful giraffes roam the savannah.  (= ACTIVE)    
The savannah is roamed by beautiful giraffes.
3. The critic wrote a scathing review.  (= ACTIVE)  
A scathing review was written by the critic.
4. The whole suburb was destroyed by the forest fire. (= PASSIVE)
The forest fire destroyed the whole suburb.
5. The kangaroo carried her baby in her pouch. (= ACTIVE)
The baby was carried by the kangaroo.