半精车外圆时要留0.6mm的磨削余量，对2×45°的导角应导成（）。
A.2×45°
B.2.3×45°
C.2.5×45°
D.3×45°
参考答案：B
China has got a good ______ for fighting against the flu with its careful and smooth organization. [ ]
A. influence
B. impression
C. knowledge
D. reputation
两岸对话与谈判“冷冻”的困难焦点在于( )
A．美国的暗中干涉
B．台湾提出“主权对等论”
C．台湾提出“一边一国论”
D．台湾当局不承认一个中国原则
