重新排列以下句子的顺序，使它们组成一段通顺的对话。

A. Oh, yes, it is. It's in the book. Thank you.

B. No, it isn't.

C. That's all right.

D. Excuse me, where's my ruler? Do you know?

E. No, I can't see it.

F. Is it in your math book?

G. Oh, sorry, I don't know. Is it in your pencil case?

H. Is it in your desk?

1.              2.              3.               4.              5.               6.               7.              8.