The questionnaire takes ________ ten to fifteen minutes to complete and can be used along with the

assessment interview. [ ]

A. mainly  

B. punctually

C. approximately  

D. precisely

事先将总体各单位按某一标志排列，然后依排列顺序和按相同的间隔来抽选调查单位抽样称为（）

A.简单随机抽样

B.类型抽样

C.等距抽样

D.整群抽样