目的分析广州市外籍人员的社会支持、网络社交、性行为特征及相关因素，为有效开展外籍人员干预活动提供参考依据。方法采用横断面调......

Dear sir or madam，　　Thank you for reading my letter. I’d like to be a volunteer of 2022 Winter Olympic Games. I think ......