Moving across the land from east to west, you come first to the famous old mountains, the Appalachian Mountains [1], which extend from the Gulf of St. Lawence [2] in Canada to the state of Alabama [3]. They run from northeast to the southwest, almost parallel to the east coast. Worn by years of rains and other kinds of weather [4]， the mountains have an average height of only 800 meters above sea level [5]. Between the mountains, there are many coal-rich valleys. The northern part of the land between the mountains and the Atlantic Ocean is mountainous and rocky [8]; the middle part，rising gently from the sea [7]，forms a narrow coastal plain; and the southern part is a wider coastal plain. To the west side of the mountains lie plateaus built up over the centuries from bits of stone washed down from the old mountains [8].
Moving westward across a large expanse of land [9], you reach the Rocky Mountains [10], the highest of all in the country. The mountains rise more than 3,000 meters above sea level with a peak Mt. Elbert about 4,300 meters high [11]. Running from the Arctic to the Mexican frontier, the mountains are often spoken of as the backbone of the continent [12]. In addition to the simpler term Rockies，the mountains are also called the Continental Divide [13] because all the rivers east of them flow into the Atlantic Ocean while the rivers on the west go to the Pacific. Tumbling up and down rapidly, the muuntains are quite rough and irregular [14].

背景介绍
这段文字介绍了美国大陆版图上的ー些山脉，它们对于美国的经济，气候、甚至是社会和文化遣产起着非常重要的作用。文中出现的地理名称并不生僻，平时如能多加积累，一定能給出约定俗成的译文。

难点分析
1. the Appalachian Mountains：mountain出现复数形式时，通常译为“山脉”。故该地名译作“阿巴拉契亚山脉”