Use the following two statements to answer this question: I. If the marginal product of labor is zero, the total product of labor is at its maximum. II If the marginal product of labor is at its maximum, the average product of labor is falling.
A. Both I and II are true.
B. I is true, and II is false.
C. I is false, and II is true.
D. Both I and II are false.
查看答案
对于深孔的钻削应采用以下哪种固定循环指令为好( )
A. G81
B. G83
C. G73
D. G82
在孔加工固定循环中,G98、G99分别为( )
A. G98返回R平面;G99返回循环起始点。
B. G98返回初始平面;G99返回R平面。
C. G98返回程序起刀点;G99返回R平面。
D. G98返回R平面;G99返回程序起刀点。
下列指令中-------指令运用于高速钻孔(断屑)()
A. G73
B. G83
C. G81
D. G82
在G73钻孔指令中,每次退刀量 ()
A. 用“R—”表示
B. 用“Q—”表示
C. 用“P—”表示
D. 由系统参数设定