From his _____ voice on the phone, I know everything is going under way. [ ]

A. satisfactory

B. satisfying

C. satisfied

D. satisfaction

转速负反馈系统在起动开始加入给定电压Ug后，此时放大环节扩大机（）。

A、处于无励磁转态，电动机没有转速

B、处于强励磁状态，输出电压迅速上升，电动机加速起动

C、以偏差电压使电动机迅速起动

D、无反馈电压，电动机不能起动