Question

阅读理解 　　About one million years ago, the Ice Age began．The Ice Age was a long period of time in which four great glaciers(冰川)pushed southward to cover almost all the upper half of North America, and then melted away．Each glacier was a thick sheet of ice and snow that spread out from a center near what is now Hudson Bay in Canada．The winters were long, and the cool summers were too short to melt much of the ice and snow．The ever-growing sheet built up to a thickness of two miles at its center． 　　As all glaciers do, these great glaciers slid(滑动)．They pushed down giant trees in their paths and scraped(刮削)the earth bare(光秃秃的)of soil．Many animals moved farther south to escape．Others stayed and were destroyed． 　　When winters of little snow came, the summer suns into the edges to the ice sheets．As the glaciers melted, rocks, soil and other things that had mixed with the ice and snow were left．New hills, lakes and rivers were formed． 　　The last of the great glaciers began its melting about 11 000 years ago．Its melting formed the Great Lakes．These lakes are today little changed from their early sizes and shapes．The largest of the North American river systems was also influenced by the glaciers．This is the Mississippi-Missouri- Ohio system．These rivers were miles wide at first．Through the years they settle into their present channels． (1) The main idea of this passage is ________． [　　] A． the Ice Age was a long period of time B． great glaciers covered North America many years ago C． changes in climate helped to melt the glaciers D． how glaciers changed North America (2) The author states that all glaciers ________． [　　] A． are two miles thick B． form frozen lakes C． are a million years old D． move and slide (3) From the information in this passage we know that ________． [　　] A． glaciers are destructive B． all glaciers in the world move southward C． the Mississippi-Missouri-Ohio systems is larger than it was before the Ice Age D． the Great Lakes are now smaller than they were before the Ice Age (4) The Ice Age lasted almost ________． [　　] A． 1 000 years B． 100 years C． 1 000 000 years D． 11 000 years (5) In the last sentence, the word “they” refers to ________． [　　] A． lakes B． rivers C． glaciers D． systems

Answer 1

答案：1．D;2．D;3．A;4．C;5．B;
解析：

(1)	第一段叙述四大冰川覆盖了北美的北部地区；中间两段主要是叙述了冰川的变化及对土地的改变；最后一段说明了北美的一些地形是由于冰川造成的。所以答案为冰川怎样改变了北美。
(2)	尽管作者写了冰川存在的时间、厚度。然而，主旨是写冰川对地形的改变，而造成这种地形改变的原因是冰川的滑动。
(3)	从第二、三段可以知道冰川是具有破坏性的，造成了对地形的改变。
(4)	第一句话“About one million years ago, the Ice Age began．”告诉我们Ice Age延续的时间为大约100万年。
(5)	最后两句话“These rivers were miles wide at first．Through the years they settle into their present channels．”说明they指的是rivers，而不是指lakes。