美国邮政管理局有着悠久的历史,它的第一届邮政局局长任命于1775年。自建立以来,由于受到各种战争、经济动荡和技术革新因素的影响,美国邮政局对其邮政结构和邮递方式进行了无数次的改进尝试。骡班邮递(19世纪至今)在邮运行业中,从快马邮递到四轮马车,动物一直都发挥着重要的作 The United States Postal Service has a long history, and its first postmaster was appointed in 1775. Since its inception, the U.S. Post Office has tried its innumerable attempts to improve its postal structure and mailing methods due to various war, economic turmoil and technological innovations. MULLIN POST (19th century to present) In the postal industry, from fast mail to Waggon, animals have been playing an important role