Here are the answers to the pronoun fill-in-the-gap exercise:
A: Let's have a takeaway tonight. Do you prefer pizza or Chinese food?
B: I don't mind. They both sound great.
A: Where were they? He tried calling her at home.
B: She was at the library helping May with his project.
A: Do you know Brian Maxwell?
B: Yes, I do. He sits next to her in Biology class. Why do you ask?
A: How does Scott know Ivan?
B: They met him at the Sports Centre. They are in the same basketball team.