TEACHER：Whose shirt is that?
　　TEACHER：Is this your shirt, Dave?
　　DAVE:    No. Sir.
　　        It's not my shirt.
　　DAVE:    This is my shirt.
　　My shirt's blue.
　　TEACHER: Is this shirt Tim's?
　　DAVE:    Perhaps it is, sir.
　　         Tim's shirt's white.
　　TEACHER：Tim!
　　TIM:     Yes, sir?
　　TEACHER：Is this your shirt?
　　TIM:     Yes, sir.
　　TEACHER：Here you are.
　　Catch!
　　TIM:     Thank you, sir.