根据对话内容，在空白处填入恰当的单词或短语，使对话完整、通顺。
A: Dale, welcome to my room!
B: Wow， ____room is nice and tidy．
A: Thanks．
B: Is this a(n) ____?
A: Yes, it is. This model plane is white. Look! Here is a yellow one．
B: ____ is that in your bookcase?
A: It's a tape player. But it's not ____.
B: Is it your brother's?
A: Yes.
B: ____the radio? Is it your brother's, too?
A: No, it's my radio．
