Problem: This book introduced Shakespeare to Goethe ; it was a major influence on *his* writing.

Do "his" and "Goethe" mean the same thing?

Answer: yes

Problem: Jim yelled at Kevin because *he* was so upset.

Do "he" and "Kevin" mean the same thing?

Answer: no

Problem: I was trying to open the lock with the key , but someone had filled the keyhole with chewing gum, and I couldn't get *it* out.

Do "it" and "the key" mean the same thing?

Answer:
no