提高听力同时，你还可以了解到美国历史上的一些重要事件。请感兴趣的你一听为快吧！
<注意>国家大写
hints：Progressive Era
During the Progressive Era, more immigrants settled in the United States. Almost 19 million people arrived between 1890 and 1921 from Russia, Poland, Greece, Canada, Italy, Mexico, and Japan. By the 1920s, citizens worried that the immigrants might take their jobs and change the culture of the United States. Although the government created quotas to restrict immigration, it relaxed those restrictions in the 1960s, assuring that the United States would remain a nation in which many different people and cultures could forge an identity as Americans.
在进步时代，更多的移民定居在美国。来自俄罗斯，波兰，希腊，加拿大，意大利，墨西哥，和日本，近19万人， 在1890年和1921年之间抵达。到20世纪20年代，市民担心的移民可能抢他们的工作，并改变美国的文化。虽然政府创建配额限制移民，但是在20世纪60年代放宽这些限制，保证美国仍将是一个国家，在许多不同的人民和文化可以伪造身份作为美国人。