什么是定额水平？
双绞线、同轴电缆和光缆也属于媒体范畴。
更换模具零件的基本原则是什么？
多媒体的集成性仅仅体现在多媒体信息方面的集成。
The damage to a vessel is over $25，000. Who must notify the nearest Coast Guard Marine Safety or Marine Inspection Office as soon as possible?（） The Master of the vessel。 The Radio Officer。 The Chief Officer。 All of the above。
Under rotary pumps are the gear, （）, cam-and-piston and screw types.
