阅读短文，判断句子正误。

Miss Li: Good afternoon, class.

Class: Good afternoon, Miss Li.

Miss Li: Sit down, please.

Liu Tao: Sorry, Miss Li. I'm late.

Miss Li: Come in, please. Don't look at the window, Mike. Open your book, please.

Mike: OK. But I can't find my book.

Miss Li: Is it in your schoolbag?

Mike: No, it isn't. 

Miss Li: Look! Your book is behind the chair.

Mike: Yes, thank you.