下面哪些是我们在设计调查问卷时应该注意的？

A、Limit the number of questions so the respondent can answer them in a minute or two.

B、Keep questions clear and simple, and not too personal.

C、Closed questions are easier to process, but open questions will collect a wider range of responses.

D、You should try putting the questions to a classmate before beginning the full survey, and be ready to modify any that were not clear.

E、Do not collect unnecessary information.