To be a good teacher, you need some of the  _ of a good actor: you must be able to hold attention and interest of your students; you must be a clear speaker, with a good, strong, pleasing voice which is fully under your control; you must be able to act what you are teaching, in order to make its meaning clear.        A good teacher doesn't sit still before his class; he stands all the time he is teaching; he walks about, using his arms, hands and fingers to help him in his explanations, and his face to express his feelings. Listen to him, and you will hear the loudness, the quality and musical note of his voice always changing according to what he is talking about.       The fact that a good teacher has some of the gifts of a good actor doesn't mean he will indeed be able to act well on the stage, for there are very important differences between the teacher's work and the actor's. The actor has to speak words he has learnt by heart; he has to repeat exactly the same words each time he plays a certain part, even his movements and the ways in which he uses his voice are usually fixed beforehand. What he has to do is to make all these carefully learnt words seem natural on the stage.       A good teacher works in quite a different way. His audience takes an active part in his play--they ask and answer questions, they obey orders, and if they don't understand something, they say so. The teacher therefore has to meet the needs of his audience. He can't learn his part by heart, because their brains couldn't keep discipline: they couldn't keep strictly to what another has written. The main difference between students and audience in the theatre is that students  _  .
move around the class keep silent all the time take an active part in class like body language