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1、The United States of AmericaAn Introduction1.Names1.The United States of America2.Abbreviated as The United States;3.America;4.US;5.the States.1.Relative LocationLocation:North America,bordering both the North Atlantic Ocean and the North Pacific Ocean,between Canada and Mexico Area:total:9,826,630
2、sq km land:9,161,923 sq km water:664,707 sq km Geography-note:worlds third-largest country(after Russia and Canada)note:includes only the 50 states and District of Columbia Area-comparative:about one-half the size of Russia;about three-tenths the size of Africa;about one-half the size of South Ameri
3、ca(or slightly larger than Brazil);slightly larger than China;about two and one-half times the size of Western Europe The maximum width of the conterminous 48 states is 4421 km.The maximum length measured from the vicinity of Brownsville,Texas,due north to the Canadian border is 2572 km.5).Populatio
4、n:Population:301,139,947(July 2007 est.)Life Expectancytotal population:78yearsmale:75.15yearsfemale:80.97years(2007est.)Landboundaries:total:12,034 km border countries:Canada 8,893 km(including 2,477 km with Alaska),Mexico 3,141 km note:Guantanamo Naval Base is leased by the US and thus remains par
5、t of Cuba Languages:English 82.1%,Spanish 10.7%,other Indo-European 3.8%,Asian and Pacific island 2.7%,other 0.7%(2000 census)note:Hawaiian is an official language in the state of HawaiiLiteracy:definition:age 15 and over can read and write total population:99%male:99%female:99%(2003 est.)Coastline:
6、Coastline:19,924 km ThreeBroadregions 1.The Atlantic Seacoast West of the Appalachians;2.The Mississippi River Basin;3.The Rockies West to the Pacific.1.The Atlantic Seacoast West of the AppalachiansA.The coastline is broken by many excellent harbors that were once important centers of commerce and
7、trade in the early days of the country.B.The Middle Atlantic States:New York,New Jersey,Pennsylvania,Maryland,Delaware,and West Virginia.C.Three important rivers in this region:the Husdson,the Delaware and the Susquehanna.D.The Appalachian Mountains.2.The Mississippi River BasinA.The Mississippi Riv
8、er Basin which is between the Appalachian and the Rockies is one of the largest areas of flatland in the world and takes up half of the United States.B.Mississippi is about 6400 km.C.The northeastern part is called the Midwest,or the Meddle West.3.The Rockies West to the PacificA.Rock mountains=the
9、Backbone of the continent;continental divide;B.Many national parks,including the Yellowstone National Park(9000 sq.km)in Wyoming,Montana and Idaho,3000geysers and hot springs in the park.C.Cascade-Sierra Nevada ranges=the great plateau areaD.Death Valley 200 km long 5-40 km wide and 86 m below sea l
10、evel.Climate:1.tropical in Hawaii and Florida,2.arctic in Alaska,3.semiarid in the great plains west of the Mississippi River,4.arid in the Great Basin of the southwest;Climate:5.low winter temperatures in the northwest are ameliorated occasionally in January and February by warm chinook(east of the
11、 Rocky Mts)winds from the eastern slopes of the Rocky Mountains2.Climate:6.New England states:cold climate7.The Middle Atlantic States:temperate climate;8.The south:a warm climate,varying with the geographical position of the individual state.3.NaturalResources RiversandLakesThe eastern United State
12、s,principal among which are the Hudson,Delaware,Susquehanna,Potomac,and Savannah;Rivers of the interior,such as the Ohio,Tennessee,Illinois,and Mississippi,often flood in spring and decrease in size during the hot weeks of late summer and the snow months of winter.The eastward-flowing Missouri,Arkan
13、sas,and Ro Grande rivers and the westward-flowing Colorado,Sacramento,Snake,and Columbia rivers.In Alaska the drainage system is dominated by the Yukon;The Great Salt Lake of Utah and many smaller salt basins The Corn Belt,a region stretching from western Ohio to central Nebraska,is the largest expa
14、nse of prime farmland in the world.Coal:more than a fifth of the worlds coal,are present within the countrys borders.The country imports more than 80 percent of its bauxite铝矾土,magnesium镁,platinum铂,tin,and tungsten钨.Natural gas:Natural gas accounted or the largest share of domestic energy production,
15、followed closely by coal and crude oil.But her big consumption still makes America to import much natural gase every year.Silver and gold:Very rich;California gold rush of 1848.The United States in the mid-1990s produced 57 percent of its petroleum needs.Elevationextremes:lowest point:Death Valley-8
16、6 m highest point:Mount McKinley 6,194 m Naturalhazards:1.tsunamis,volcanoes,and earthquake activity around Pacific Basin;2.hurricanes along the Atlantic and Gulf of Mexico coasts;3.tornadoes in the midwest and southeast;4.mud slides in California;5.forest fires in the west;6.flooding;permafrost in northern Alaska,a major impediment to development