“Is she going to the post office?” “No,_____.”

A．she doesn’t

B．she goes by bike

C．to the shops

D．she’s on the bike

减速器是指原动机与工作机之间独立封闭式传动装置，用来降低转速并相应的增大转矩，绝对不可能增加工作机的速度。