28.Here are three students.They're good friends.Their names are Jim,Eric and Helen. Jim found a notebook in the school library.It's a black notebook.Is it yours?Please call him.His phone number is 345-7438. Eric lost a set of keys in the classroom.Now he must find them.Can you help Eric?Please call him at 456-9807.You can e-mail him at eric2268@163.com.jye.ai,too. Here is a CD player on Helen's desk.But it isn't hers.Is it Jim's?No,Jim's CD player is in his room.Is it Eric's?No,Eric's CD player is on his desk.Is it yours?Ask Helen's English teacher for it.The teacher's phone number is 568-4239.
(1)Is 456-9807 Jim's phone number?
(2)What does the underlined word "them" refers to(指的是)?