应急指挥平台系统摄像机串口的设置（）同实际连接的串口一致，否则不能控制摄像机。
A.必须
B.可以
C.不可以
D.均可以
参考答案：A
--- How did you pay these worker Well, as a rule they were paid _____.
A．on the hour
B．by the hour
C．to the hour
D．with the hour
板材常用的连接方式有（）。
A、咬接
B、粘接
C、焊接
D、铆接
