Problem: This book introduced Shakespeare to Ovid ; it was a fine selection of *his* writing.

Are "his" and "Shakespeare" the same?
Answer: no

Problem: In the storm, the tree fell down and crashed through the roof of my house. Now, I have to get *it* removed.

Are "it" and "the roof" the same?
Answer: no

Problem: I sat there feeling rather like a chappie I'd once read about in a book , who murdered another cove and hid the body under the dining-room table , and then had to be the life and soul of a dinner party, with *it* there all the time.

Are "it" and "book" the same?
Answer: no

Problem: The signs over the shops' doors had pictures that indicated what work was done inside. Although more and more people were learning how to read, each artisan still had signs, not wishing to lose a possible patron merely because *he* happened to be illiterate.

Are "he" and "patron" the same?
Answer:
yes