A:What a mess! I can see a mouse on your desk!

B:Oh yes, there is another mouse under the desk. It's beside the schoolbag.

A:But where is the cat?

B:It's behind the curtain. Maybe it doesn't see the mice.

A:It's terrible. Let's tide our classroom.

B:OK.

A:We must clean our desk first. Let the cat catch the mice please.

B:Ok, and you put the book and pencil case in the schoolbag. Oh, there is a pen under the chair. Please pick it up