用穿镗法镗削孔壁间距较大或需镗同一轴线上的多个同轴孔的箱体时，为了提高各孔之间的同轴度误差可用支承套镗孔。
参考答案：对
---Look, the teacher is explaining something to her students again and again.
---________the teacher is!
A．what patient
B．How patient
C．What a patient
D．How patient a
MACD由正负差和异同平均数两部分组成，前者是辅助，后者是核心。 ( )
