Canadian Shield
【正确答案】：1）A big piece of rock dominates the Canadian landscape. 2）It is called the Canadian Shield. It consists of some of the world’s oldest rocks, dating back nearly 4 billion years, and covers almost half of the country’s surface area. 3）Shaped somewhat like a giant saucer, it sweeps from the Amundsen Gulf southward and eastward across the top of the Prairies and around Hudson Bay to the Atlantic Ocean, covering most of Ontario and Quebec and all of Labrador. 4）The Shield also underlies the sedimentary rocks that make up the remainder of the country’s surface and near surface.
【题目解析】：
参见教材P260。
