When I first learned to write in English，I ran into much difficulties. The main problem was in that I always thought in Chinese and tried to translate anything into English. My teacher advised me to keep my diary. I followed her advice and should put down 100 words or so each day. Soon I began to enjoy talk to myself on paper as I was learning to express me in simple English. One day I wrote a little story and showed to my teacher. She liked it very much and reads it to the class. All said the story was a good one. Their word were a great encouragement to me.

弯制卡环转弯的要点，下述哪项是错误的

A．定点
B．定向
C．控制用力的大小
D．定位
E．控制卡环臂进入倒凹的深度