[填空题]Let’s proceed to the main exhibit hall and look at some of the actual vehicles that have played a prominent role in speeding up mail delivery. Consider how long it used to take to send a letter across a relatively short{{U}} (36) {{/U}}. Back in the 1600’s it took two weeks on{{U}} (37) {{/U}}to get a letter from Boston to New York, a distance of about 260 miles. Crossing a river was also a{{U}} (38) {{/U}}. Ferry service was so{{U}} (39) {{/U}}that a carrier would sometimes wait hours just to catch a ferry. For journeys inland, there was always the stagecoach, but the ride was by no means{{U}} (40) {{/U}}because it had to be{{U}} (41) {{/U}}with other passengers. The post office was pretty ingenious about some routes. In the nineteenth century, in the Southwestern desert, for instance, camels were{{U}} (42) {{/U}}in to help get the mail through. In Alaska, reindeer were used. This practice was discontinued because of the{{U}} (43) {{/U}}temperament of these animals.

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