【简答题】建立相对独立的平面坐标系统,应当与国家坐标系统相联系。一个城市能建设( )个相对独立的平面坐标系。
【单选题】听力原文:M: How much is an airmail letter to Japan? W: I'll have to check. Can I help you with anything else? M: I'd like a 20-cent stamp, please. W: There you are. Where are the two speakers?
【单选题】听力原文:W: What help do you need? I'll try to help you. M: I'm going to attend an international convention in Harbin for two weeks. I have no clothes for that cold climate. Since you have been to the Nor...
D.
To make a tour of China.
【多选题】建立相对独立的平面坐标系统的原则是( )。
【多选题】(4 选2)利用载波信号频率的不同,实现电路复用的方法有( )和( )。
【单选题】采用DDC实现对照明系统的监控,其方法(不考虑调光)是通过在DDC中编制( )实现。
【多选题】建立相对独立的平面坐标系统的原则是______。