数控编程数控车加工零件时，对刀点一般来说就是（）。
A.换刀点
B.编程原点
C.机床原点
D.机床零点
参考答案：B
The police finally caught up with the man ______ was the escaped prisoner.
A．who they thought
B．whom they thought
C．they thought him
D．that they thought him
求板AB上所受的水平总压力Px及垂直总压力Pz（AB为1/4圆弧，宽1m）。
