Bill is at home reading a book in his bedroom. His sister is in the living room watching TV. His parents are still at work. At four o'clock, the doorbell rings. Bill runs down the stairs and answers the door. It is his friend Mark. “Where is Scott?” asks Bill. “He has to help his father,” replies Mark. “His mother said he cannot go to the park with us. Can we use your football this time as I cannot find mine? Let's go!”