单项选择题
An optical cable is used to transmit：（）
A.digital audio from a component to a receiver. B.analog video from a component to a receiver. C.analog audio from a component to a receiver. D.digital video from a component to a receiver.
单项选择题 共同赔偿机关承担（）
单项选择题 On a laptop, special operations like wireless card on/off, volume settings, and screen brightness can generally be controlled via which of the following physical means?（）
填空题 销售时点系统也称为（）
