单项选择题

案例分析题

At the bottom of the world lies a mighty continent still wrapped in the Ice Age and，until recent times，unknown to man.It is a great land mass crisscrossed （交叉往来）by mountain ranges whose【C1】______and height are still uncertain.Much of the continent is a complete blank on our maps.A 1000-mile【C2】______of the coastline has never been【C3】______by any ship.Man has【C4】______，on foot，less than one percent of its area.
Antarctica differs slightly【C5】______the Arctic regions.The Arctic is an ocean，covered with【C6】______packed ice and surrounded by the land masses of Europe，Asia，and North America.The Antarctic is a continent 【C7】______as large as Europe and Australia 【C8】______，centered roughly on the South Pole and surrounded by the most【C9】______water areas of the world—the Atlantic，Pacific and Indian Ocean.
The continental ice pack is more than two【C10】______high at its center；thus，the air over the Antarctic is far more refrigerated （冰冻的）than it is over the Arctic regions.This cold air falls 【C11】______the land with such force that it 【C12】______the nearby seas the stormiest in the world and renders【C13】______those regions whose【C14】______at the opposite end of the globe are inhabited.【C15】______，more than a million persons live【C16】______2000miles of the North Pole in an area that【C17】______most of Alaska，Siberia，and Scandinavia a【C18】______rich in forest and mining industries.Except for a handful of【C19】______stations，within the same distance of the South Pole there is not a（an）【C20】______tree，industry，or settlement.

【C1】（）