Today we're going to discuss the history of the postal service. In the 19th century, mail was delivered by train, which was fast but limited to major routes. Then, in the early 20th century, the introduction of motor vehicles allowed for more flexible door-to-door delivery. However, it wasn't until the 1920s that airmail became practical, significantly reducing delivery time for long distances. Interestingly, the first regular airmail service in the United States began in 1918, but it was initially used only for government documents. By the 1930s, commercial airlines took over airmail, making it more efficient and cheaper for the public.
❓ 机动车在邮件投递中的主要优势是什么?
A. A. 它们比火车还快。
B. B. 它们使得更加灵活的门到门配送成为可能。
C. C. 他们降低了邮资成本。
D. D. 它们能够承载更重的负载。
✅ 正确答案
B. They allowed for more flexible door-to-door delivery.