提高聽(tīng)力同時(shí)，你還可以了解到美國(guó)歷史上的一些重要事件。請(qǐng)感興趣的你一聽(tīng)為快吧！

<注意>國(guó)家名大寫(xiě)
hints：Louisiana Territory;Florida
The U.S. doubled in size when it bought the Louisiana Territory from France in 1803 and Florida from Spain in 1819. From 1816 to 1821, six new states were created. Between 1812 and 1852, the population tripled. As the country grew, differences among the states became more obvious. The United States was a country of civilized cities and lawless frontiers. The United States loved freedom but also tolerated slavery. The differences began to create problems.
當(dāng)它從法國(guó)購(gòu)買(mǎi)了路易斯安那州的領(lǐng)土在1803年從西班牙購(gòu)買(mǎi)佛羅里達(dá)州在1819年，美國(guó)的規(guī)模擴(kuò)大了一倍。從1816年到1821年，創(chuàng)建了6個(gè)新的州。 1812年和1852年間，人口的三倍。隨著國(guó)家的發(fā)展，各國(guó)之間的分歧變得更加明顯。美國(guó)是一個(gè)國(guó)家文明城市和不法前沿。美國(guó)熱愛(ài)自由，但也容忍奴隸制度。差異開(kāi)始產(chǎn)生問(wèn)題。