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, andFrance 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 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 descend 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 roar down from the polar plateau to the sea. Left bare are spectacular gorges, rippled fields of sand dunes, clusters of boulders(大圆石)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 that they may carry a message of hope for the verdant(草木繁茂的)parts of the earth. Some scientists believe that in some cases the dry valleys may soak up pollutants faster than pollutants enter them.
1．Antarctica is scientifically important in that _______.
A．it is a space station
B．it is an ideal place for the investigation of glaciology
C．there is the mysterious dry valley
D．it can help people detect global environmental changes
2．The reason for the disappearance of glaciers in the dry valley is_______.
A．that they’ve descended to the Ross sea
B．that they’ve been blasted out by vicious winds
C．the global warming trend ever since the ice age
D．that they’ve been changed into gorges, sand dunes and boulders
3．When the author calls Antarctica“distant-early-warning sensor”, he actually means that_______.
A．such equipment has been set up for scientific purpose
B．the research groups there are like such kind of sensors
C．potential global changes can be seen on Antarctica first
D．Antarctica is remote from other parts of the earth
4．Which of the following statements is true according to the article?
A．There is a cluster of island west of the Transantartic Mountain.
B．Scientific research on Antarctica only centers on the ice and snow there.
C．Dry valleys may be a place to dispose of our pollutants.
D．All the countries on earth should be concerned about the health of the West Antarctic Ice Sheet.
5．The word“spotted”(2nd paragraph) can best be replaced by _______.
A．placed
B．noticed
C．fixed
D．judged
