DJ6型光学经纬仪的安置工作包括（）和（）。
When you connect an external monitor to your portable computer, the same image appears on both monitors. You need to drag a window from one monitor to the other. What should you do?（） ["A","B","C","D"]
桑代克提出的学习规律包括（）。 ["强化律","练习律","准备律","效果律","同化律"]
混凝土强度等级是用边长（）的立方体试块确定的。 ["50m","l00m","150mm","75mm"]
滑车是（）。 ["简易起吊工具","动力设备","牵引设备","降机"]
中心监控站操作视屏化的基本概念是什么？
