当加工的孔需要依次进行钻削、扩削、铰削多种加工时，应采用（）。
A.固定转套
B.可换钻套
C.快换钻套
D.都可以
参考答案：C
—How did you manage to get such a nice old painting?
—Quite _____. [ ]
A. by accidents
B. by a chance
C. by accident
D. by incident
心包压塞体征中不包括
A．发绀B．心包摩擦音C．颈静脉怒张D．脉速，脉压小E．肝大，下肢水肿
