电液执行器行程通过调整（）的零点和量程电位器来完成。
A.控制卡
B.反馈卡
C.阀位传感器
D.显示卡
参考答案：A
--- ___________________
--- I’m being served. Thank you anyway.
A．May I have the bill?
B．Can I take your order?
C．How would you like your coffee?
D．What about eating out?
计算-2+3的结果是 [ ]
A．1
B．-1
C．-5
D．-6
