补全对话（每空一词） 。
A: Mum, I've lost my art book.Have you 1._____ it anywhere?
B: Is it the book 2._____ a red cover?
A: Yes, that's 3_____ ! Where did you 4._____ it
B: Sorry, I 5._____ seen it 6._____ .7._____ you tried to look 8._____ it under your bed?
Maybe you dropped (丢) it there.
A: Oh! Here it 9._____ . 10._____ goodness!?
B: You should 11._____ more careful from now on.?
A: Yes, it won't happen (发生) 12._____.
