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Passage
One
To
create a supercell, take a storm where wind speed increases
with height, while wind direction veers; a situation in
which updraughts and downdraughts within the thunderstorm
can support each other's existence rather than cancel each
other out. It is as winds blow into this turbulent region
from three to five kilometers up that a low-pressure section
of the storm may begin to rotate.
The rotation of this part of the storm (known
as a mesocyclone) causes the air pressure to fall some more,
prompting wind lower down to flow into the storm and speed
up upwards. This creates a spinning updraught which high-level
winds in the storm can boost in the same way that wind blowing
across the top of a chimney does wonders for drawing up
an open fire.
You're not yet looking at a tornado, though
if you're watching this particular storm develop you might
start looking for a getaway car —especially if the storm
begins to change shape. When mid-to upper-level winds upwind
of the storm encounter the supercell, some are forced to
detour round it. They converge again downwind, moulding
the storm clouds into an ominous anvil-shape in the process.
But while some wind goes round the mesocyclone, some runs
full square into this meteorological brick wall and is forced
downward, creating a "rear flank downdraught" (RFD) which
many experts believe is what makes or breaks a tornadic
storm.
It's when an RFD tries to swing around the
base of the storm, narrowing the area of wind flowing into
the updraught and increasing its spin (in the same way figure
skaters when their arms are pulled in) that you might want
to get into your getaway car. If you're anywhere beneath
whirling piece of meteorological give and take—a funnel
cloud—you are in a bad, dangerous place known to stormchasers
as "the bear cage". It's where, if the funnel cloud sticks
around long enough for the updraught to touchdown on terra
firma, you will find yourself on the inside of a tornado.
( 337 words)
1. One of the factors that create a supercell
is that ________. ( A
)
(a) updraughts and downdraughts are supportive to each other
(b) updraughts undermine downdraughts
(c) the storm should be in low-pressure section three kilometers high
(d) wind blows faster while rising higher but the direction unchanged
2. When the storm rotates, ________. (
B
)
(a) air pressure will go on increasing
(b) it starts from the low-pressure section
(c) wind will join the storm in setting an open fire
(d) an updraught will be replaced by a downdraught
3. What can be inferred from the third paragraph?
(
B)
(a) If an updraught is created, tornado appears.
(b) A tornado comes into being when a RFD is created.
(c) RFD is created if winds go round the mesocyclone.
(d) When meeting supercell, winds will blow in all directions.
4. If you were caught by a tornado, which of
the following statement is NOT right? (
D
)
(a) You must have been in "the bear cage".
(b) It should have been the updraught that got you.
(c) The funnel cloud must have kept running around.
(d) The updraught should not have touched the ground.
5. What is NOT mentioned in the article? (
A
)
(a) RFD swings around the top of the storm.
(b) RFD accelerates the spin of updraught.
(c) Tornado develops through several stages.
(d) During the process, some winds are forced to swing around the supercell
and gather again downwind.
TOP
Passage
Two We've all read global-warming scare stories.
Though some scientists insist there is cause for alarm,
evidence indicates otherwise. Global warming may be coming,
but if it does, it won't necessarily be extreme. And it
might actually be a boon for the environment.
When Senator Mitchell presented his doomsday
scenario, crude computer climate models were predicting
two to three times as much warming as they currently do.
Now researchers say that the earth is likely to warm by
about three degrees Fahrenheit during the next century.
That may sound a lot, but it isn't. The
world has experienced approximately that much warming fairly
recently in history. And we loved it! Between A.D.900 and
1300, the earth warmed by some three degrees. Scholars refer
to that period—one of the most favorable in human history—as the Medical Climate Optimum.
Food production surged, many scientists
believe, because winters were milder and growing seasons
longer. Key agricultural regions experienced fewer floods
and droughts. (There was more rainfall, but it evaporated
more quickly.) Death rates declined in many places, partly
because of the decrease in hunger and partly because people
spent less time huddled in damp, smoke-filled hovels that
helped spread tuberculosis and other infectious diseases.
Prosperity stimulated an outpouring of creativity—in architecture, art and practical invention. In Europe,
artisans built the soaring cathedrals that even today stun
tourists with their beauty and engineering excellence. In
Southeast Asia, the Khmer people built the huge temple complex
of Angkor Wat.
Trade flourished, in part because there
were fewer storms at sea. The Vikings discovered Greenland
around 950. It was so warm there that colonists supported
themselves by pasturing cattle on what is now frozen tundra.
Farming moved farther north in Scandinavia,
Russia and Japan. England was warm enough to support a thriving
wine industry.
We know less about what went on in North
America. We do know that the Great Plains, the upper Mississippi
Valley and the Southwest apparently received more rainfall
than now. The Anasazi civilization grew abundant irrigated
crops—and then vanished when the Medieval Optimum ended
and rainfall declined.
There were negatives, of course. The steppers
of Asia and parts of California, for instance, suffered
dry periods. But over all, the medieval experience with
global warming should reassure us greatly.
(378 words)
6. It can be
inferred from the beginning part of the passage that ________. ( C
)
(a) global
warming is threatening our life
(b) there have been enough evidence to show the negative effects of global
warming
(c) global warming is not such a disastrous phenomenon as commonly believed
(d) global warming might do harm to the living surroundings
7.
It is suggested that Senator Mitchell is ________ about/to the coming of
global warming.
(
B
)
(a) optimistic
(b) pessimistic
(c) neutral
(d) indifferent
8. The Anasazi civilization vanished because
________. (
B
)
(a) global warming brought about too much rainfall
(b) it was not so warm as before and the rainfall declined
(c) too many irrigated crops were planted
(d) crops were over-irrigated
9. On the whole, in the period of the Medieval
Climate Optimum, ________ under the influence of global
warming. ( A
)
(a) culture, trade and farming got fully developed
(b) food production was well controlled
(c) nature disasters like floods and droughts came more often
(d) death rate declined all over the world
10. Which
of the following statements is true according to the text?
(
A
)
(a) The period of global warming in Medieval times is one of the most favorable
period.
(b) The earth is likely to warm by three degrees in the next century, which
is unprecedented.
(c) The medieval global warming did not influence our life much.
(d) The medieval global warming didn't make life hard in any aspect.
TOP
Passage
Three
El Niño has for centuries been a regular,
if somewhat reckless, climatic event. It typically makes
its presence felt around midwinter, hence a name that loosely
translates as "Christ child" in the Spanish of the Peruvian
fishermen who first noticed it. El Niño begins, however,
some months prior to that, when trade winds in the western
tropical Pacific drop or even shift, switching from blowing
westward to the east. When this happens, a body of warm
water that normally pools in the ocean east of Australia
begins to move toward the coast of Peru. Warm air rising
from the surface of this mass—which is as much as 12F
warmer than normal—acts like a paddle stuck into the southern
jet stream, redirecting it northward and altering weather
from Australia to Canada to Africa. The warm water itself,
meanwhile, is like a cap on a bottle when it hits the coast
of Peru, halting the rise of cold, nutrient-rich water that
typically emerges along the South American coast from deep
in the Pacific. That drastically affects the food chain
for marine mammals, birds, and fish.
Scientists have grown steadily more familiar
with El Niño in the past 20 years. "There's been a fundamental
change since the 1982-' 83 El Niño, the devastating event
the 1997-' 98 El Niño surpassed in size," says McPhaden,
"We didn't even know that one was happening until it was
almost over. In the 1997-98 El Niño, we could tell you day
by day what was happening." The reason? Two new powerful
tools—instrumented satellites and buoys—now make it
as easy for scientists to watch the ocean as if it were
a wading pool in their backyard.
Still, scientists were disappointed by one
significant aspect of the past year's work on El Niño: their
ability to forecast it accurately. While a few computer
models suggested that an El Niño would develop in 1997,
none came close to predicting its scope or the speed with
which it developed. Even the gold standard of forecasting
turned into lead. A model developed by Mark Cane and Steven
Zebiak was considered the best among El Niño forecasting
models. But it didn't read the global tea leaves correctly,
forecasting an El Niño that was much later and smaller than
the one that actually hit.
( 383 words)
11. According
to the article, what is NOT true about El Niño ? (
D
)
(a) It is most obvious in mid-winter
(b) It makes its appearance months before mid-winter
(c) It has influence upon the food chain
(d) It starts from the coast of Peru
12.When El Niño occurs, ________.
(
C
)
(a) it doesn't change its direction all the way
(b) the warm air rising from the sea is much warmer than normal
(c) the trade winds in the Pacific blow eastward
(d) weather changes from Africa to Australia in turn
13. What's the fundamental change since 1982-'83
El Niño? (
A
)
(a) El Niño can be observed closely with instrumented satellites and buoys.
(b) 1997-'98 Niňa was more severe than ever.
(c) scientists can observe El Niño daily on spot.
(d) El Niño is steadier and easy to observe.
14. Concerning the prediction of El Niño, which
statement is NOT true? (
D
)
(a) A comprehensive and precise prediction is still out of way.
(b) One of the best forecasting models failed to predict El Niño properly.
(c) Even what is considered perfect standard of prediction didn't work well.
(d) The computer models can predict the scope or speed of El Niño.
15.The prediction for 1997-'98 El Niño failed,
because ________.
(
B
)
(a) scientists didn't rely on computer models
(b) computer models were incapable of predicting some aspects of El Niño
(c) computer models were not properly managed
(d) El Niño is too changeable to be predicted
TOP
测验结果：15 题中 共答对题， 答错题，
还有题未答。
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