According to the questionnaire network, the survey has been approved by the Science and Technology Ethics Committee of Shanghai University. The purpose of the questionnaire survey is to provide basic data support for academic research and government decision-making consultation, without asking personal names, specific addresses and other private information. The number drawn is hidden by the system, so the interviewer can't see the real number of the respondent. The project team and researchers will abide by the ethical requirements of social investigation and scientific research.