从方框中的A-G选项中选择适当的句子将对话补充完整,有两个多余选项。

A. No, it isn't. B. Yes, it is. C. They are her pencil case and baseball. D. Where is her hat? E. It's on the chair. F. What's this? G. It's a baseball.

A: Hi, Grace! ____
B: It's a photo of Anna's room.
A: ____
B: It's on the bed.
A: Is her alarm clock on the bed?
B: ____ It's on the desk.
A: Well, where is her backpack?
B: Look! ____
A: And what are those on the floor?
B: ____ The pencil case is red, and the baseball is white.

若 $\frac{x^2-y^2}{a^{2}x-a^{2}y}$ ÷ $\frac{{\left(x+y\right)}^2}{ax+ay}$ 的值是5,则a的值是(   )

国际社会的最基本成员是（  ）

a, great, Shanghai, is, city (.)
____

下列各组物质以任意比混合后充分燃烧，产生的CO₂分子数目一定比H₂O分子数目多的是                                                          （   ）