1. It is my friend's family. My friend's father is the manager a trading company. My friend`s mother is a teacher. 2. She took today's mail. 3. Give me the customers' letters, please. 4. This is our director's office. 5. Whose computer is this? - It's Peter's. 6. Whose letters are these? - These are our customers' letters. 7. Read the business partners' letters, please.