开放作文。

     请根据下面提示，写一篇短文。词数不少于50。

     In your spoken English class, your teacher shows you the following picture. You are asked to describe

the picture and explain how you understand it.

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简单头帽口外牵引矫治器的禁忌症是（）。

A.下颌平面角过小的安氏Ⅱ类错，下颌逆时针方向旋转生长者

B.骨性或牙性安氏Ⅱ类错

C.增加上颌磨牙支抗

D.拔牙病例可内收尖牙及切牙

E.可用于抑制上颌骨的向前生长