导读（Guided Reading）
作为国名，“美国”是个简称，其全称为“美利坚合众国”。英文表述为America、The United States和The United States of America。但是需要指出的是，America有美洲的意思，所以正式场合下用The United States或者The United States of America更为妥当和确切。
1776年7月4日独立之初，美国仅拥有北美洲沿大西洋一边的一块狭长地带。历经200多年的西进运动、战争攫取、低价购买和领土吞并，现今美国的土地横跨北美大陆，并延伸至北美洲西北角的阿拉斯加和地处北太平洋的夏威夷，国土总面积为937万平方公里，居世界第四（此数据为中国官方网站提供的信息；美国官方网站称其国土面积为960万平方公里，居世界第三）。
美国首都是华盛顿，即哥伦比亚特区华盛顿（Washington,District of Columbia）。取名华盛顿是为了纪念美国首任总统乔治·华盛顿（George Washington）；用哥伦比亚则是为了不忘美洲新大陆“发现者”克里斯托弗·哥伦布（Christopher Columbus）。1790年美国国会定都华盛顿，正式启用是1800年。
美国国旗由红白色相间的条纹和蓝底白色的星星组成，常被人们称作为“星条旗”（Stars and Stripes）。“星条旗”上有13道条纹，代表北美最早独立时的13个州；星星共有50颗，表示美国现有50个州。
美国国土的主要部分位于北美洲中央地带，东临大西洋，北与加拿大毗邻，南同墨西哥接壤，西濒太平洋。美国本土东西长4500公里，南北宽约为2700公里。在这片幅员辽阔、地形多变的土地上，有曲折的海岸、广袤的平原、起伏的丘陵、逶迤的山脉，还有宽广无垠的草原、低洼荒芜的沼泽和贫瘠荒凉的沙漠。
美国地形构造的特征是东西两侧高，中间低平，没有东西走向的横向山脉，只有行列式南北走向的山岭。大致而言，美国本土分为三个地形区，即东部（大西洋沿岸低地至阿巴拉契亚山脉）、中部（阿巴拉契亚山脉和落基山脉之间的大平原）和西部（落基山脉以西至太平洋）。
美国大陆的地理位置介于北纬25º至49º之间，除佛罗里达半岛属于热带气候外，大部分属于暖温带和亚热带范围。大陆以外的两块领土，阿拉斯加州位于北纬60º至70º，属于寒冷气候区；夏威夷州位于北回归线以南的地区，属于热带气候区。
美国的主要河流包括：密西西比河、密苏里河、俄亥俄河、田纳西河、阿肯色河、科罗拉多河、哥伦比亚河、哈德逊河、特拉华河和波托马克河等。美国的湖泊主要有东北部的五大湖和西部大盆地的大盐湖。五大湖位于加拿大和美国的边境上，由苏必利尔湖、密执安湖、休伦湖、伊利湖和安大略湖所组成，是北美洲最大的淡水湖区。大盐湖在美国的犹他州内，其大小和形状随雨量多少而变化。天气极其干燥时，盐湖甚至会干涸。
学习要点（Learning Objectives）
（1）Know the general geographicalfeatures of the United States.
（2）Understand climatic variations indifferent areas.
（3）Be informed of the characteristics offour geographical regions .
中心问题（Project）
TheUnited Statesis said to be anation of expansion. How hasAmericaexpanded its territory from the colonial period to the resent?
生词与词组（New Words and Expressions）
Caribbean 加勒比海的
tame 驯服，控制并利用
topographical 地形的
framework 构造
Appalachians 阿巴拉契亚山脉
Cordilleras 科迪勒拉山系的北美部分
Sierra Nevada 内华达山脉
Cascade Range 喀斯喀特山脉
intermontane 山间的
plateaus 高原
landform 地貌
Arctic 北极的
rainfall 降雨量
drought 干旱
dormant 潜伏的，搁置不用的
luxuriant. 茂盛的，郁郁葱葱的
grazing land 放牧地
northernmost 最北的
southernmost 最南的
swampy 多沼泽的
play out 完成
ecologist 生态学家
vegetation 植物、草木
oasis (复数oases) （沙漠中）的绿洲
semi-arid 半干旱的
static 静态的、不变的
prairie 大草原
正文（Text）
The Face of the Land
With a total area of 9,363,123 square kilometers, theUnited Statesis exceeded in size only byRussia,Canada,andChina.The forty-eight states lie between the Atlantic and Pacific Oceans,CanadaandMexico.The two states that share no boundaries with the rest of the country, Alaska and Hawaii, arelocated in the far northwest corner of the continent and the middle of the Pacific Ocean, respectively. Widely separated possessionsin the Caribbean and the Pacific add another17,6000 square kilometers to American territory.
The most striking feature of the country, however, is not its sizebut its diversity. Its natural environment varies from the arctic to thetropical, from rainforest to desert, from vast plains to cliffs and mountainspeaks. It is often said that theUnited Statesis a nation with anabundance of geography, but a shortage of history. There is some truth in thestatement, for theUnited Statestook over most of its territorywithin the last two centuries. Even today, much of theUnited Statesremains only thinlypopulated and hardly tamed by civilization.
America’sgeological and topographical framework is built around a huge interior lowlandthat has produced some ofAmerica’sgreatest agricultural and mineral wealth, contains a large portion of itspopulation, and is the heartland of what American politicians like to call “Middle America”. The region is drained by the Mississippi River, one of the largest navigable riversystems in the world. The Mississippi is notmerely a useful river; it also severs as a geographic symbol---the traditionaldividing line inAmericabetween “East” and “West”.
The mountain ranges on east and west coastlines differ from eachother quite substantially. The Appalachians on the east stretch almost unbrokenfrom Alabamato the Canadian border and beyond. While this costal region contains noremarkable scenery, nor much mineral wealth, it was here that the Americannation was planted and took root in the 17th century. The originalthirteen centuries were all located in this narrow belt, and almost half ofAmerican history has been played out here. It was not until the AmericanRevolution (1775-1781) that significant numbers of American settlers began tomove westward across the Appalachians into theinterior lowlands.
On the west coast lies the mighty system of mountains that Spanishexplorers named the “Cordilleras”---a collective term for all the high roughcountry of the western third of theUnited States. This western countryis both complicated and varied, containing not only some of the highestmountains in North America, but also a vastexpanse of intermontane basins, plateaus, and isolated ranges. Taken together,America’sWest is a land of impressive scenery, considerable environmental variety, andgreat mineral wealth. It is hardly surprising that much of this western countrywas settled by adventurous people in search of quick riches, and freedom fromthe traditions of the crowded and long-settled East.
Climate
Owing to its vast size and the varied landforms, theUnited Stateshas a wide range of climates fromTropical climate in Hawaii to the extremelycold Arctic climate in Alaska.The climate of the Continental U.S. also varies considerably.
Take the East for example, it is a quite humid region that includesalmost half of the present-dayUnited States. Throughout the whole region, droughtis a rare occurrence, and annual rainfall is quite high. In its northernmostarea, the winters are quite long and very cold, resulting in short growingseason. Southward, the temperature moderates, with a longer growing season,milder winters, and hot summers. Still farther southwest, there lies aninvisible but crucial line, the northern boundary ofAmerica’s most distinctive region.Ecologists call it “a humid subtropical forest”, but to most Americans, this issimply “the South”, with a long hot summers and a long growing season. Thesouthernmost area is the only genuinely tropical part of theUnited States, aside from Hawaii. The land there is low and swampy andremote from the nation’s main population centers.
By contrast, the West is a dry and arid land. There is the desertthat lies in the rain-shadow of the Sierra Nevada and Cascade mountain rangesand stretches north fromMexicoto southern Oregon.Rainfall in this dry area is both scarce and undependable, and the onlyimportant human settlement occurs in irrigated oases. Most of the oases supportagriculture and a few are the seats of major cities. Outside the oases,however, the desert is empty with sparse vegetation and little surface soil. Then,there is also a semi-arid or dry West, where there are periods of plentiful rainfalland periods of severe drought. When rains are plentiful, grasses there growhigh and green, and farmers and ranchers can expect a good harvest.
Between the humid East and the arid West, there is the great zone oftransition, known as the humid-arid transition. This great stretch of landoffers fine farmland---some of the nation’s best---with deep black prairiesoil. In dry years, the native grasses stay brown and dormant, storing moisturein their roots. In moist years, the grass turns green and luxuriant. Such landcan be fine grazing land for native buffalo or domestic cattle; but it can alsobe used to grow wheat and produce bumper crops. Thanks to the advancedtechniques developed in farming, this region has become the nation’s richestagricultural area---the “Barn of America”, or the Grain Belt of America.
Regional Geography
A country as diverse and as large as theUnited Stateswas almost bound toevolve different conditions of life in different areas. The contrast betweenNew England and Virginiabecame apparent early on in colonial period. The former, due to its shortergrowing reason, was less dependent on agriculture and more reliant on trade andindustry, owing to its easier access to, and greater use of water power. Thelatter, by contrast, has a much warmer and more productive climate and soil,and subsequently has always placed a great deal of emphasis on agriculture,particularly on commercial and industrial crops.
Of course, regions do not remain static; they change with time andtechnological progress. With the development of industrial revolution, regionsin theUnited Stateshave witnessed great changes over the past two centuries. They are less andless the direct result of nature, and more and more the work of human beings. Consequently,the regional geography of theUnited Statesis no longer simply its natural regionsin human expression Rather, human beings have increasingly come to put theirown interpretation on nature, subordinating natural conditions to economic andsocial needs and purposes. As human beings have been able to draw some naturalregions together, or divide up others, they have come to play an increasinglyimportant role in the writing of geography. In 18th-centuryAmerica,for example, geographical regions were smaller, based on sea and rivertransportation, and more involved in primary production. As roads and railwaysdeveloped, as marketing became better organized, and more importantly asindustries expanded, the regions became larger and more distinctive.
Over the past two hundred years or so, Americans have tried todivide their country into many different regions. In 1819, for example, Morse, “thefather of American geography”, divided theUnited Statesinto four regions, namely: New England, the Mid-Atlantic States, the South, and the West. In 1910,however, the U.S. Census Bureau divided the country into nine major sections:New England, the Mid-Atlantic States, the EastNorth-Central States,the West North-CentralStates, the SouthAtlantic States,the East South-CentralStates, the WestSouth-Central States,the Mountain States,and the Pacific Coast States.More recently, theUnited Statesis commonly divided into four major regions: Northeast, South, Midwest, and West.
The Northeast stretches from Mainethrough Maryland and west to the border of Ohio. This section isdensely populated and highly urban, often viewed as the nation’s economic andcultural center. The South traditionally refers to the eleven states that leftthe Union during the Civil War. Nowadays,however, such states as West Virginia, Kentucky, Missouri, and Oklahoma are often addedto the list of Southern states. As for the Midwest, it includes the statesboarding the Great Lakes and the first tiers of states west of the MississippiRiver from Missouri and Kansasnorth toCanada.Of all the major cities in the Midwest, Chicagois the region’s most important city, the home of widely diversified industriesand cultural institutions.
注释\解释（Notes and Explanations）
TheAmerican Revolution----Also known as the War ofIndependence or Revolutionary War, it began in 1775 and concluded in 1783. Itended two centuries of British rule for most of the North American colonies andcreated theUnited States of America.
TheGreat Lakes------These are the most important lakesinAmerica, extending about1600 kilometers and forming a section of the boundary between theUnited StatesandCanada.
TheCivil War----- The Civil War in theUnited States, which began in1861and ended in1865), was fought over the secession of the Confederate States. Inresponse to the election of Abraham Lincoln as President, 11 southern slavestates declared their secession from theUnited Statesand formed the Confederate States ofAmerica;the other 25 states supported the federal government. After four years ofwarfare, the Confederacy surrendered and slavery was outlawed everywhere in thenation.
