题目内容：

根据情景完成对话.
A：——1
B:That bike?No!It belongs to my brother.
A:——2
B：Yes,this one is mine.
A:Is this your CD?
B:No,it isn't.
A:3——is it?
B:It belongs to Peter.
A:4——?
B：No,they aren't mine.
A:Whose books are they?
B:They 5——my sister.
A:Is this your brother's hat?
B:No,it isn't.
A:Whose hat is it then?
B:6——
A：Oh,it's yours.