Problem: The sculpture rolled off the shelf because *it* wasn't anchored.

Do "it" and "The sculpture" mean the same thing?

Answer: yes


Problem: The sack of potatoes had been placed above the bag of flour , so *it* had to be moved first.

Do "it" and "The sack of potatoes" mean the same thing?

Answer: yes


Problem: The delivery truck zoomed by the school bus because *it* was going so fast.

Do "it" and "the school bus" mean the same thing?

Answer:
no