Problem: I took the water bottle out of the backpack so that *it* would be handy.

Do "it" and "the water bottle" mean the same thing?

Answer: yes


Problem: Mark told Pete many lies about himself, which Pete included in his book. *He* should have been more skeptical.

Do "He" and "Pete" mean the same thing?

Answer: yes


Problem: John was doing research in the library when he heard a man humming and whistling. *He* was very annoying.

Do "He" and "John" mean the same thing?

Answer:
no