錾削硬钢或铸铁等硬材料时,楔角应取()
A. 50-60°
B. 60-70°
C. 40-50°
喷油泵每次泵出的油量取决于柱塞的有效行程的长短,而改变有效行程可采用()
A. 改变喷油泵凸轮轴与柴油机曲轴的相对角位置
B. 改变滚轮体传动部件的高度
C. 改变柱塞斜槽与柱塞套油孔的相对角位置
Then the bank manager introduced him to their accountants who advise companies about
While the companies are busy doing their business, the accountants are busy looking