Miss Wang will come to Beijing ____ two days. [ ]
A. after
B. in
C. on
D. before
答案:B
采用热套法把轴承套在轴径上,应先将轴承放在变压器油中加热0.5h左右,加热油温为()℃。
A.80~100;
B.150~200;
C.45~55;
D.500。
抽样方法不包括()
A.随意抽样
B.系统抽样
C.分层抽样
D.整群抽样
E.单纯随机抽样