()是在先期完成的选择调查课题、初步探索、提出研究假设等几项工作的基础上进行的。
A.选择调查对象
B.分发问卷
C.回收问卷
D.设计问卷
参考答案:D
She _______________ her homework last night. [ ]
A. didn't
B. doesn't
C. didn't do
D. doesn't do
轴承零件探伤结束,良好轴承零件逐件进行()处理。
A.清洁
B.擦拭
C.退磁
D.涂油