主减速器的作用是
A．减小扭矩，降低转速
B．降低转速，增大扭矩
C．增大转速，增大扭矩
D．增大附着力
参考答案：B
My good performance in the job interview left me about my future and about what I can do here.
A．puzzled
B．sensitive
C．optimistic
D．embarrassed
简述β受体阻断药的外周β受体阻断及其效应变化。
