常用的二次接线图有哪些种类？
参考答案：
常用二次接线图有原理接线图、展开接线图和安装接线图等三种。
右图是古代某一时期行政区划局部地图，根据图中信息判断该历史地图最可能是
A．周朝
B．秦朝
C．宋朝
D．元朝
According to the speaker, the proportion of college students with loans in the United States has increased from 50% in 1993 to about 67% at present and the average loan debt when they graduate is 17,000 dollars.
