5W【最新】四级预测题【实用】
先给一部分看看，好的话给点mp，因为太穷啦
北京大学
part ⅱ
reading comprehension (35 minutes)
passage one
questions 21 to 25 are based on the following passage.
antarctica has actually become a kind of space station—a unique
observation post for detecting important changes in the world’s
environment.s1 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
distantearly 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
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 100mileanhour
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.
21.antarctica is scientifically important in that ____.
a) it is a space stationb) it is an ideal place for the
investigation of glaciology
c) there is the mysterious dry valleyd) it can help people detect
global environmental changes
22.the reason for the disappearance of glaciers in the dry valley
is ____.
a) that they’ve desended to the ross seab) 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
23.when the author calls antarctica “distantearlywarning
sensor”, he actually means that ____.
a) such equipment has been set up for scientific purposeb) 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
24.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.
25.the word “spotted”(2nd paragraph)can best be replaced by____.
a) placedb) noticed c) fixedd) judged
