第四天通关自测

第四天通关自测

第一篇

Japanese Drilling into Core of Earth

In what resembles a journey to the center of the Earth,Japanese scientists have launched the world’s first attempt to bore a hole into the red-hot core of a volcano and unlock the secrets of deadly eruption.

A 50-meter-high oil-rig-like derrick perched on the scrubby slopes of Japan’s Mount Unzen will begin drilling through the volcano’s crust next week in a bid to sample the magma bubbling below.

The aim is to study how the liquefied rock causes menacing gas buildup,said team leader Setsuya Nakata,of the University of Tokyo’s Earthquake Research Institute.

“Gassing is important because it controls the explosivity of eruptions,”Nakata said.“The results can be expanded to anti-disaster research.”

Mount Unzen,a wind-swept 1,486-meter dome on the southern island of Kyushu,is a perfect model.It erupted in 1991,showering avalanches of hot rocks over a nearby town,killing 43 people and leaving nearly 2,300 homeless.Another 11,000 people were evacuated from the area until 1995, when the volcano had stabilized.

The results are particularly important to a nation like Japan,where the meteorological agency monitors 20 dangerous peaks.Perhaps Japan’s most famous volcano is snowcapped Mount Fuji, which last erupted in 1707 and sprinkled Tokyo with ash.

The drilling on Mount Unzen will begin very soon from an altitude of 850 meters on its northwest slope.Scientists hope to tap a magma vent around sea level by August and extract a 200-meter-long core sample by summer 2004.

Boring into the glowing magma at that level would normally be impossible,because of its fiery 700 degree Celsius heat.Thus,slurry of water will be pumped into the drill shaft to cool the magma and allow the drill head to cut through.

Nakata said there is no danger of triggering another eruption.

1.According to the passage,Mount Unzen

A.erupted in 1707.

B.erupted in 1991.

C.erupted in 1995.

D.erupted several times in the last century.

2.According to the passage,the study of the Mount Unzen volcano may benefit Japan in all the following aspects EXCEPT

A.finding causes of volcano eruptions.

B.helping to launch anti-disaster research.

C.looking into the connection between liquified rocks and gas buildup.

D.predicting volcano eruptions.

3.Why is this research project so important to Japan?

A.Because Japan has many living volcanos.

B.Because Japan wants to turn Mount Fuji to a dead volcano.

C.Because volcano gas could be a source of energy.

D.Because Japan is testing a new way of drilling into the earth.

4.The drilling site on Mount Unzen is

A.around the sea level.

B.on the northeast slope of the mountain.

C.about half way up the mountain.

D.as high as 1,486 meters.

5.The title of this passage Japanese Drilling into Core of Earth actually means that they

A.drill a hole into the core of a volcano.

B.bore into the rocks near the volcanic vent.

C.conduct an imagery journey to the core of a volcano.

D.regard magma as the core of Earth.

第二篇

A Sunshade for the Planet

Even with the best will in the world,reducing our carbon emissions is not going to prevent global warming.It has become clear that even if we take the strongest measures to control emissions,the uncertainties in our climate models still leave open the possibility of extreme warming and rises in sea level.At the same time,resistance by governments and special interest groups makes it quite possible that the actions suggested by climate scientists might not be implemented soon enough.

Fortunately,if the worst comes to the worse,scientists still have a few tricks up their sleeves. For the most part they have strongly resisted discussing these options for fear of inviting a sense of complacency that might thwart efforts to tackle the root of the problem.Until now,that is.A growing number of researchers are taking a fresh look at large-scale“geoengineering”projects that might be used to counteract global warming.“I use the analogy of methadone,”says Stephen Schneider,a climate researcher at Stanford University in California who was among the first to draw attention to global warming.“If you have a heroin addict,the correct treatment is hospitalization,and a long rehab.But if they absolutely refuse,methadone is better than heroin.”

Basically the idea is to apply“sunscreen”to the whole planet.One astronomer has come up with a radical plan to cool Earth:launch trillions of feather-light discs into space,where they would form a vast cloud that would block the sun’s rays.It’s controversial,but recent studies suggest there are ways to deflect just enough of the sunlight reaching the Earth’s surface to counteract the warming produced by the greenhouse effect.Global climate models show that blocking just 1.8 per cent of the incident energy in the sun’s rays would cancel out the warming effects produced by a doubling of greenhouse gases in the atmosphere.That could be crucial,because even the most severe emissions-control measures being proposed would leave us with a doubling of carbon dioxide by the end of this century,and that would last for at least a century more.

1.According to the first two paragraphs,the author thinks that

A.strong measures have been taken by the government to prevent global warming.

B.to reduce carbon emissions is an impossible mission.

C.despite the difficulty,scientists have some options to prevent global warming.

D.actions suggested by scientists will never be realized.

2.Scientists resist talking about their options because they don’t want people to

A.know what they are doing.

B.feel their efforts are useless.

C.think the problem has been solved.

D.see the real problem.

3.What does Stephen Schneider say about a heroin addict and methadone?

A.Methadone is an effective way to treat a hard heroin addict.

B.Methadone is not a correct way to treat a heroin addict.

C.Hospitalization together with methadone can work effectively with a heroin addict.

D.Methadone and heroin arc equally effective in treating a heroin addict.

4.What is Stephen Schneider’s idea of preventing global warming?

A.To ask governments to take stronger measures.

B.To increase the sunlight reaching the Earth.

C.To apply sunscreen to the Earth.

D.To decrease greenhouse gases.

5.What is NOT true of the effectiveness of“sunscreen”according to the last paragraph?

A.It deflects sunlight reaching the Earth to counteract the warming.

B.It blocks the incident energy in the sun’s rays.

C.It is a controversial method.

D.It decreases greenhouse gases in the atmosphere.

第三篇

Plant Gas

Scientists have been studying natural sources of methane for decades but hadn’t regarded plants as a producer,notes Frank Kepler,a geochemist at the Max Planck Institute for Nuclear Physics in Heldelberg,Germany.Now Kepler and his colleagues find that plants,from grasses to trees,may also be sources of the greenhouse gas.This is really surprising,because most scientists assumed that methane production requires an oxygen-free environment.

Previously,researchers had thought that it was impossible for plants to make significant amounts of the gas.They had assumed that microbes need to be in environments without oxygen to produce methane.Methane is a greenhouse gas,like carbon dioxide.Gases such as methane and carbon dioxide trap heat in Earth’s atmosphere and contribute to global warming.

In its experiments,Kepler’s team used sealed chambers that contained the same concentration of oxygen that Earth’s atmosphere has.They measured the amounts of methane that were released by both living plants and dried plant material,such as fallen leaves.

With the dried plants,the researchers took measurement at temperatures ranging from 30 degrees Celsius to 70 degrees C.At 30 degrees C,they found,a gram of dried plant material released up to 3 nanograms of methane per hour.(One nanogram is a billionth of a gram.)With every 10-degree rise in temperature,the amount of methane released each hour roughly doubled.

Living plants growing at their normal temperatures released as much as 370 nanograms of methane per gram of plant tissue per hour.Methane emissions tripled when living and dead plant was exposed to sunlight.

Because there was plenty of oxygen available,it’s unlikely that the types of bacteria that normally make methane were involved.Experiments on plants that were grown in water rather than soil also resulted in methane emissions.That’s another strong sign that the gas came from the plants and not soil microbes.

The new finding is an“interesting observation,”says Jennifer Y.King,a biogeochemist at the University of Minnesota in St.Paul.Because some types of soil microbes consume methane,they may prevent plant-produced methane from reaching the atmosphere.Field tests will be needed to assess the plant’s influence,she notes.

1.What was scientists’understanding of methane?

A.It was produced from plants.

B.It was not a greenhouse gas.

C.It was produced in oxygen-free environments.

D.It traps more heat than any other greenhouse gas.

2.To test whether plants are a source of methane,the scientists created.

A.an oxygen-free environment.

B.an environment with the same concentration of oxygen as the Earth has.

C.a carbon dioxide-free environment.

D.an environment filled with the greenhouse gas.

3.Which statement is TRUE of the methane emissions of plants in the experiment?

A.The lower the temperature,the higher the amount of methane emissions.

B.Living plants release less methane than dried plants at the same temperature.

C.When exposed to sunlight,plants stop releasing methane.

D.The higher the temperature,the greater the amount of methane emissions.

4.Which of the following about methane is NOT mentioned in the passage?

A.Plants growing in soil release methane.

B.Plants growing in water release methane.

C.Soil microbes consume methane.

D.Microbes in plants produce methane.

5.What is the beneficial point of some microbes consuming plant-produced methane?

A.Methane becomes less poisonous.

B.Methane is turned into a fertilizer.

C.Less methane reaches the atmosphere.

D.Air becomes cleaner.

Keys:B D A C A C C A C D C B D C D

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