调速系统的作用是保持汽轮机在额定转速下稳定运行，调整进汽量，以适应电力负荷变化的需要。
参考答案：错
句型转换。
1. Do you have a baseball bat? (改为肯定句)
_____ _____ a baseball bat.
2. We have a ping-pong club. (改为否定句)
We _____ _____ a ping-pong club.
3. Sue plays tennis with her mother. (改为一般疑问句)
_____ Sue _____ tennis with her mother?
4. Jiang Cheng has a computer. (对画线部分提问)
_____ Jiang Cheng _____?
5. Betty's keys are in the drawer. (对画线部分提问)
_____ _____ Betty's keys?
与图像显示上下位置偏移有关的操作是（）
A.病人摆位左右偏离
B.扫描机架倾角过大
C.床面升降调节有误
D.床面进出调节有误
E.扫描野选择有误
