15.
A. Landlord and lodger.
B. Receptionist and guest.
C. Salesman and client.
D. Policeman and driver.
16.
A. Take the safety of his parents-in-law into account.
B. Ask his parents-in-law to make the decision.
C. Invite his parents-in-law to a sight-seeing restaurant.
D. Buy his parents-in-law some pets instead.
