阅读以下1-5段材料，然后从A-f中选出各段的主题。有一项为多余选项。

A. A good teacher acts in class

B. Acting: repetition of fixed words and movements

C. Teaching: a student-centered creative process

D. Similarities between teaching and acting

E. ( = AB) Differences between teaching and acting

F. ( = AC) A good teacher, not necessarily a good actor

       1   To be a good teacher, you need some of the gifts of a good actor: you must be able to hold the

attention and interest of your audience; you must be a clear speaker, with a good, strong, pleasing voice

which is fully under your control; and you must be a- ble to act what you are teaching, In order to make

its meaning clear.

         2   Watch a good teacher, and you will see that he does not sit unmoved before his class: he stands

the whole time he is teaching; he walks about, using his arms, his hands and fingers to help him in his

explanations, and his face to express feeling. Listen to him, and you will hear the loudness, the quality and

the musical note if his voice always changing according to what he is talking a- bout. 

       3   The fact that a good teacher has some of the gifts of a good actor doesn't mean that he will indeed

be able to act well in the stage, for there are very important differences between the teacher's work and the

actor's. The actor has to speak words which 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 and actions seem natural on

the stage. 

        4     A good teacher works in quite a different way. His audience takes an active part in his play: they

ask questions, they obey orders, and if they don't understand something, they say so, the teacher therefore

has to suit his act to the needs of his audience. He cannot learn his part by heart, but must invent it as he

goes along. 

       5    As a good teacher presently, you must take your au- dience as your friends, take care of them, help

them and give them enough freedom and space. I have known many teachers who were fine actors in class

 but were unable to take part in a stage play be- cause their brains wouldn't keep discipline: they could not

keep strictly to what another had written.