公共英语四级辅导：PETS4阅读精讲（43）

　　Reading Comprehension
　　Read the following two texts. Answer the questions below each text by choosing A, B, C or D. The panoramic View of the United States
　　On a topographic map of the United States, the mountains look like jagged masses, the plains like vast open flat spaces, and the rivers like meandering thread. Today, highways and railways crisis-cross the land, making travel easy. But only a few generations ago,the topographic features on the map represented great dangers and difficulties. Today ‘s visitors, riding over a good road in the Cascade Mountains in the west coast states of oregon and Washington may see marks on the rocks made by ropes where pioneer settlers painfully lowered their hours and wagons down cliffs to reach the fertile river valley far below. In the Sierra Nevada Mountain of California, the main route now runs through a mountain pass which was once too narrow for a wagon to go through. pioneer families reaching that pass had to take their wagons apart piece by piece, carry them through, and then, reassemble them on the other side.
　　Modern means of communication and transportation have enabled man to overcome these obstacles. poles and wire now carry electrical power and telephone communication over ridges that are so deep in snow that only persons wearing snowshoes or skis can reach them. Railroads run along the sides or mountains or in tunnels through the burning heat of deserts.
　　Much of the geography and history of the United States was determined some 10.000 to 25.000 years ago. At that time, the northern ice cap flowed over the North American continent and ground into it a number of major changes. These ice flows determined the size and drainage of the great lakes. They changed the direction of the Mississippi River. They pushed soil off a huge part of Canada into the United States, thus created the northern part of the Central Agricultural Basin--one of the richest farming areas in the world.
　　on the Atlantic shore of the United States, much of the northern coast is rocky and uninviting, but the middle and southern Atlantic coast rises gently from the sea. It starts as low, wet ground and sandy flats, but then becomes a rolling coastal lowland somewhat like that of northern and western Europe. The Appalachians, which run roughly parallel to East Coast, are old mountains with many coat-rich valleys between them. To the west of the Appalachians lie plateaus built up over the centuries from bits of stone that were washed down fro the mountains and then cut into small hills by streams. Beyond is the great Central Lowland that, in its configuration, resembles the plains of Eastern Europe, or Manchuria, or the Great plains of Australia, or certain plains in Africa or South America.
　　North of the Central Lowland, extending for almost 1.600 kilometers, are the five Great Lakes which the United States shares with Canada. The lakes, estimated to contain about half of the world’s fresh water, were gauged out of the land by the ice that once covered the northern United States.
　　West of it are the Great plains, likened to the flat top of a table which is slightly titled upward to the west. They are stopped by the Rocky Mountains, the backbone of the continent. The Rockies are considered young mountains: of the same age as the Alps in Europe, the Himalayas in Asia. Like these ranges, they are high, rough and irregular in shape.
　　1. The title of the passage “the panoramic view of the united states” means _____.
　　A. the over-all view of the United States
　　B. the mountainous view of the united states
　　C. the views of great plains of the United States
　　D. the coastal view of the United States
　　2. What happened to the early pioneer settlers when they tried to go through the mountains to the valleys?
　　A. they had roads as good as today’s
　　B. they met a lot of difficulties
　　C. they had to use ropes
　　D. they had to use narrower wagons
　　3. Today, those obstacles in the mountains areas are overcome _____.
　　A. by using snowshoes and skins
　　B. by using ropes and wagons
　　C. by using modern means of communication and transportation
　　D. taking the wagons apart piece by piece and reassembling them
　　4. The direction of the Mississippi River was changed by _____.
　　A. the ice flows some 10.000 to 25.000 years ago
　　B. the drainage of the Great Lakes
　　C. the soil that was pushed off from parts of Canada into the United States
　　D. by the size of the Great Lakes
　　5. Which mountain range is considered the backbone of the American continent?
　　A. the Alps
　　B. the Appalachians
　　C. the Sierra Nevada Mountains
　　D. the Rockies