无线电高度表的发射机和接收机（）.
A.必须共用同一部天线
B.使用各自的天线
C.的收发天线类型不同
D.发射时不允许接收
参考答案：B
He arrived here at noon, ﹍﹍in the day, and he went out and came back﹍﹍in the day.
A．late; late
B．late; later
C．later; late
D．later; later
原理图与PCB的元件映射关系是由什么维护的（）。
A.元件标号
B.UniqueID
C.元件的Comment
D.库链接的DesignItemID
