补全对话 （每空一词）。
A: Where l. _____ my book?
B: I 2. _____ know. 3. _____ it in your backpack?
A: No, it 4. _____
B: Is 5. _____ on your desk?
A: 6. _____, it isn't.
B: Is 7. _____ on the teacher's desk?
A: No, it 8. _____
B: Oh, look! 9. _____ 10. _____ your desk.
A: I see it, too. Thanks.