频敏变阻器其构造与三相电抗相拟，即由三个铁芯柱和（）绕组组成。
A、二个
B、一个
C、三个
参考答案：C
—What were you up to when she dropped in?
—I _________ for a while and __________ some reading.
A．was playing; was going to do
B．played; did
C．had played; was going to do
D．had played; did
配碴整形车走行系统挡位开关转至作业挡、空挡、走行挡时，如挂上挡则相对应的（）亮。
