For years，scientists and others concerned about climate change have been talking about the need for carbon capture and storage （CCS）.
   That is the term for removing carbon dioxide from，say，a coal-burning power plant's smokestack and pumping it deep underground to keep it out of the atmosphere，where it would otherwise contribute to global warming.
   However，currently，only one power plant in Canada captures and stores carbon on a commercial scale （and it has been having problems）.Among the concerns about storage is that carbon dioxide in gaseous or liquid form that is pumped underground might escape back to the atmosphere.So storage sites would have to be monitored，potentially for decades or centuries.
   But scientists at Lamont-Doherty Earth Observatory at Columbia University and other institutions have come up with a different way to store CO₂ that might eliminate that problem.Their approach involves dissolving the gas with water and pumping the resulting mixture — soda water，essentially — down into certain kinds of rocks，where the CO₂ reacts with the rock to form a mineral called calcite（方解石）.By turning the gas into stone，scientists can lock it away permanently.Volcanic rocks called basalts（玄武巖） are excellent for this process，because they are rich in calcium，magnesium and iron，which react with CO2.
   The project called CarbFix started in Iceland，2012，when the scientists pumped about 250 tons of carbon dioxide，mixed with water，about 1，500 feet down into porous basalt.Early signs were encouraging：The scientists found that about 95 percent of the carbon dioxide was changed into calcite.And even more importantly，they wrote，the change happened relatively quickly — in less than two years.
   "It's beyond all our expectations，" said Edda Aradottir，who manages the project.Rapid change of the CO₂ means that a project would probably have to be monitored for a far shorter time than a more conventional storage site.
   There are still concerns about whether the technology will prove useful in the fight against global warming.For one thing，it would have to be scaled up enormously.For another，a lot of water is needed — 25 tons of it for every ton of CO₂ — along with the right kind of rock.
   But the researchers say that there is enough porous basaltic rock in Iceland，including in the ocean floors and along the margins of continents.And sitting a storage project in or near the ocean could potentially solve the water problem at the same time，as the researchers say seawater would work just fine.

（1）What can we learn about CCS in Paragraphs 2 and 3？

C

C

A．Scientists believe global warming will be avoided if CO₂ is pumped underground.
B．It's been a common practice in many plants to capture and store CO₂ underground.
C．There is no guarantee that CO₂ will not escape even if pumped underground.
D．It requires decades to turn CO₂ into liquid form and be locked underground.
（2）What materials should be involved in the project CarbFix？

D

D

A．Water，CO₂，soda water and basalts
B．W ater，soda water，a pump and calcite
C．CO₂，basalts，a pump and calcite
D．Water，CO₂，a pump and basalts
（3）According to Edda Aradottir，the result of the project was beyond the researchers' expectations，because

B

B

.
A．it's disappointing to discover new problems caused by rapid change
B．it's amazing to see 95% of the carbon dioxide turn into calcite that fast
C．it's puzzling to find the encouraging but unexpected result of the project.
D．it's exciting to sense the problem of storing CO₂ likely to be solved
（4）What is the author's purpose in writing the passage？

A

A

A．To inform us of a breakthrough in storing CO₂.
B．To praise the efforts of scientists in storing CO₂.
C．To show the different ways to fight against CO₂.
D．To urge people to produce the least possible CO₂.