数控加工前,工艺员要编写(),目的是为了选用适合加工的数控铣床,准备刀具和夹具,最后要编写程序。
A.加工过程卡片
B.加工工艺
C.零件加工顺序
D.加工工序卡
参考答案:D
—This pair of shoes belong to Jack. He likes this kind very much.
—It __ be his. It's too large for him. [ ]
A. can; can't
B. may; needn't
C. must; mustn't
D. must; can't
在用电梯安全定期监督检查周期为()。
A.半年
B.1年
C.2年
D.3年