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．