Antarctica has actually become a kind of
space station a unique observation post for detecting important changes in the
world’s environment. Remote from major sources of pollution and the complex
geological and ecological systems that prevail elsewhere, Antarctica makes
possible scientific measurements that are often sharper and easier to interpret
than those made in other parts of the world.
Growing numbers of scientists therefore see
Antarctica as a distant-early-warning sensor, where potentially dangerous global
trends may be spotted before they show up to the north. One promising field of
investigation is glaciology. Scholars from the United States, Switzerland, and
France are pursuing seven separate but related projects that reflect their
concern for the health of the West Antarctic Ice Sheet a concern they believe
the world at large should share.
The Transantarctic Mountain, some of them
more than 14,000 feet high, divide the continent into two very different
regions. The part of the continent to the "east" of the mountains is a high
plateau covered by an ice sheet nearly two miles thick. "West" of the mountain,
the half of the continent south of the Americas is also covered by an ice sheet,
but there the ice rests on rock that is mostly well below sea level. If the West
Antarctic Ice Sheet disappeared, the western part of the continent would be
reduced to a sparse cluster of island.
While ice and snow are obviously central to
many environmental experiments, others focus on the mysterious "dry valley"of
Antarctica, valleys that contain little ice or snow even in the depths of
winter. Slashed through the mountains of southern Victoria Land, these valleys
once held enormous glaciers that descended 9,000 feet from the polar plateau to
the Ross Sea. Now the glaciers are gone, perhaps a casualty of the global
warming trend during the 10,000 years since the ice age. Even the snow that
falls in the dry valleys is blasted out by vicious winds that roars down from
the polar plateau to the sea. Left bare are spectacular gorges, rippled fields
of sand dunes, clusters of boulders sculptured into fantastic shapes by
100-mile-an-hour winds, and an aura of extraterrestrial desolation.
Despite the unearthly aspect of the dry
valleys, some scientists believe they may carry a message of hope of the verdant
parts of the earth. Some scientists believe that in some cases the dry valleys
may soak up pollutants faster than pollutants enter them.
1. What is the best title for this
[A] Antarctica and environmental
[B] Antarctica: Earth’s Early-Warning
[C] Antarctica: a Unique Observation
[D] Antarctica: a Mysterious
2. What would the result be if the West
Antarctic Ice Sheet disappeared?
[A] The western part of the continent would
[B] The western part of the continent would
[C] The western part of the continent would
become scattered Islands.
[D] The western part of the continent would
be reduced to a cluster of Islands.
3. Why are the Dry Valleys left
[A] Vicious wind blasts the snow
[B] It rarely snows.
[C] Because of the global warming trend and
[D] Sand dunes.
4. Which of the following is true?
[A] The "Dry Valleys" have nothing left
[B] The "Dry Valleys" never held
[C] The "Dry Valleys" may carry a message of
hope for the verdant.
[D] The "Dry Valleys" are useless to
1. A 2. D 3. C 4. C