完整版新编英美概况许鲁之第四版Unit7课后习题简答题答案VIP免费

Unit 1 Geographical Features and Natural Resources 1. How many states are there in the United States? And which two states are geographically separated from the others? (50, Alaska, Hawaii) 2. What are the general characters of the Rocky Mountains and the Appalachian Mountains. 1) To the west of Atlantic coastal plain lie the Appalachian Mountains that begin in Canada and reach all the way to Georgia and Alabama. These are old mountains with rounded tops and wooded hills, usually not exceeding 800m in height. The highest point is only 2000m above the sea. Most of the mountain ridges are low enough to be easily crossed by modern highways. The Appalachians have much beautiful scenery and many tourist resorts. The Ohio and the Tennessee Rivers flow down the western slopes of the Appalachians to the great Mississippi River, deep in the heart of America. 2) To the west of the Great Plains lie the Rocky Mountains, “the backbone of the continent”. These high mountains stretch all the way from Mexico to the Arctic and form what is known as Continental Divide, or Great Divide, the most important watershed on the continent. The Rockies are more than twice as high as the Appalachians and high enough to receive more rain than the surrounding plains and plateaus. Consequently, they are mostly forested. The striking and varied scenery of the Rockies has given rise to the establishment of many national parks here. The other natural wonders include roaming herds of buffalo, elk, deer, antelope and sheep, as well as the famous grizzly bear. Chapter 2 American Population 1. Why is the United States known as a “meltingpot ”?It means that the US is composed of immigrants from different nations all...