chapter 13 geography 地理位置
1.Alaska and Hawaii are the two newest states in American.Alaska northwestern Canada，and Hawaii lies in the central Pacific.
2.The U.S has a land area of 9.3 million square kilometres.It is the fourth largest country in the world in size after Russia，Canada and China.
3.Of all states of American，Alaska is the lagest in area and Rhode Island the smallest.But on the mainland Texas is the largest sate of the country.
4.The Rockies，the backbone of the North American Continent，is also known as the Continental Divide.
5.The two main mountain ranges in American are the Appalachian mountains and the Rocky mountains. The Appalachians run slightly from the northeast to southwest and the Rocky mountains run slightly from the northwest to southeast.
6.The Mississippi River is the largest river in American，over 6000 kilometers.The Mississippi has been called father of watersor old man river
7.The Ohio river has been called the American Ruhr，As in Germany， the area along the river is rich in valuable deposits of high-grade coking coal and is well known for its steel industry.The river provides cheap water transportation for raw materials.
8.On the Pacific side there are two great rivers：the Colorado in the south and the Columbia ，which rises in Canada.
9.The Rio Grande River forms a natural boundary between Mexico and the United States.
10.the most important lakes in the United States are the Great Lakes. They are Lake Superior，which is the largest fresh water lake in the world， Lake Michigan ，the only entirely in the U.S.，Lake Huron，Lake Eire and Lake Ontario.They are located between Canada and the United States except Lake Michigan.