从方框中选择最佳选项完成对话, 有两项多余。

A. Don't worry. B. Let's look for it together. C. What's the matter? D. Whose backpack is this? E. It can't be mine. F. You are welcome. G. I think I might leave it in the reading room.

A: Anna, you look worried.  

B: I can't find my backpack anywhere. Where can it be?

A:  Let's see where it might be.

B: But it isn't there.

A: What color is your backpack?  

B: It's black and white.

A: Oh, look! Is this one yours?

B: No.  Mine is newer than this one.