When Americans first move from eastern coast to the western coast, there were no airplanes, trains or automobiles. 美国人第一次从东海岸向西海岸迁移的时候，没有飞机、火车或汽车。

　　Then, how could they move? 那么，他们是怎样迁移的呢？

　　They used wagons. 他们使用马车。

　　Moving from the eastern coast to the western coast was really a long trip. 从东海岸向西海岸迁移的路途很遥远。

　　They could meet wild animals or Indians. Or they could get lost. 他们可能会碰到野生动物或印第安人，或者迷路。

　　Therefore, the travelers traveled together. 因此，这些人结伴而行。

　　They traveled in a straight single line. 他们以直线的方式行进。

　　If you saw them, you might think they looked like a train. 如果你看到它们，你可能会觉得它们像火车。

　　So, this group of wagons are called a wagon train. 因此，这样的车队被称为马车队。

　　At night, they formed a circle with their wagons and took a rest. 晚上，他们用马车围成一个圈，然后休息。