at the beginning of a survey, what i should say to interviewee?

[Mulin]

at the beginning of a survey, what i should say to interviewee?
"could you have time to finish this questionnaire?" is this expression right?

[Mister Micawber]

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No, 'could' is probably not correct. It is difficult to judge the correct question, though. Has the interviewee sat down to be interviewed, or is s/he just a potential interviewee? Is s/he aware of the nature of the request at the time of this question? Give us a bit of context, please.
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_________________
Native English teacher at Mister Micawber's

[Mulin]

my survey is about the most concerned issues by australians
the interviewees are random. in other words, every people is potential interviewee. they do not know the nature of this question before i give them a questionnaire.

[Mister Micawber]

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Perhaps: "Excuse me. Would you have time to complete a brief survey for me? It is on the issues of concern to Australians."
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_________________
Native English teacher at Mister Micawber's