直流发电机——直流电动机自动调速系统采用变电枢电压调速时，实际转速（）额定转速。
A、等于
B、大于
C、小于
D、不小于
参考答案：C
His speech was too boring, but I _____ during the listening.[ ]
A. try to sleep
B. tried to sleep
C. tried not to sleep
D. try not to sleep
简述群体归属和群体规范对传播效果影响的主要表现。
