second class mail造句

postal services-quality of service-measurement of the transit time of end-to-end services for single piece non-priority mail and second class mail
邮政服务.服务质量.单件非优先邮件和二级邮件全程服务运送时间的测量
postal services-quality of services-measurement of the transit time of end-to-end services for single piece non-priority mail and second class mail; german version en 14508 : 2003
邮政服务.服务质量.单件非优先邮件和二级邮件全程服
It's difficult to find second class mail in a sentence. 用second class mail造句挺难的