双微机调速器具有（）调节规律。
A、PI
B、PD
C、PID
参考答案：C
Please open your L/C immediately to facilitate（）.
A.our shipping arrangement
B.for shipment
C.to arrange shipment
D.us to arrange shipment
十进制数60转换成二进制数是( )。
A．0111010 B．0111110 C．0111100 D．0111101
