4. My cat died.
   - No change (already in passive voice).

5. I agree with Dr. Ikeda's theory.
   - Dr. Ikeda's theory is agreed with by me.

6. Dr. Ikeda developed that theory.
   - That theory was developed by Dr. Ikeda.

7. Timmy dropped the cup.
   - The cup was dropped by Timmy.

8. The cup fell to the floor.
   - No change (already in passive voice).

9. The assistant manager interviewed me.
   - I was interviewed by the assistant manager.

10. It rained hard yesterday.
    - No change (already in passive voice).

11. A hurricane destroyed the small fishing village.
    - The small fishing village was destroyed by a hurricane.

12. Dinosaurs existed millions of years ago.
    - No change (already in passive voice).

13. A large vase stands in the corner of our front hallway.
    - No change (already in passive voice).

14. The children seemed happy when they went to the zoo.
    - No change (already in passive voice).

15. After the class, one of the students always erases the chalkboard.
    - After the class, the chalkboard is always erased by one of the students.

16. The solution to my problem appeared to me in a dream.
    - I was appeared to in a dream by the solution to my problem.

- My cat died yesterday.
2- I agree with Jim’s theory.
3- Dr. Ikeda developed that theory.
4- Tim dropped the cup.
5- The cup fell on to the floor.
6- The manager will interview me.
7- They have gone to the shop.
8- A hurricane destroyed the small fishing village.
9- The solution to my problem appeared to me in a dream.
10- After class, one of the students always erases the chalkboard.
11- When did someone invent the radio?
12- My grandfather planted this tree 50 years ago.
13- Mary has just washed those dishes.
14- They are going to build a new hospital here.
15- What should we do now?
16- We can do nothing to help her.
17- When is someone going to announce the result of the contest?