由于交流伺服电动机的转子制作的轻而细长，故其转动惯量较小，控制较灵活；又因转子电阻较大，机械特性很软，所以一旦控制绕组电压为零，电机处于单相运行时，就能很快的停止转动

--His mother dances well.

-- So _____ and so _____.

A．she does; his father does

B．does she; his father does

C．she does; does his father

D．does she; does his father