A:Now let's begin the class . Who is on duty today ? B: I am , sir . A: Please come to the front to have <MASK> ' free talk in English . Very well ! Whose turn is it to have a free talk ? B: It's me , sir . But I am sorry I have forgotten to prepare for it . A: Well . Don't forget to perform your duty next time , ok ? Now , let's start our lesson .
five minutes 20 seconds four hours