If two scientists at Los Alamos National Laboratory are correct, people will still be driv

If two scientists at Los Alamos National Laboratory are correct, people will still be driving gasoline-powered cars 50 years from now, giving out heat-trapping carbon dioxide into the atmosphere — and yet that carbon dioxide will not contribute to global warming.
In a proposal by two scientists, vehicle emissions (排放) would no longer contribute to global warming. The scientists, F. Jeffrey Martin and William L. Kubic Jr., are proposing a concept, which they have named Green Freedom, for removing carbon dioxide from the air and turning it back into gasoline.
The idea is simple. Air would be blown over a liquid solution (溶液) of potassium carbonate, which would absorb the carbon dioxide. The carbon dioxide would then be put to chemical reactions that would turn it into fuel: gasoline or jet fuel.
This process could change carbon dioxide from an unwanted, climate-changing pollutant into a vast resource for renewable fuels. The cycle — equal amounts of carbon dioxide produced and removed — would mean that cars, trucks and airplanes using the synthetic (合成的) fuels would no longer be contributing to global warming.
Although they have not yet built a synthetic fuel factory, or even a small model, the scientists say it is all based on existing technology. “Everything in the concept has been built, is operating or has a close cousin that is operating,” Dr. Martin said.
The Los Alamos proposal does not go against any laws of physics, and other scientists who have independently suggested similar ideas. Dr. Martin said he and Dr. Kubic had worked out their concept in more detail than previous proposals.
There is, however, a major fact that explains why no one has built a carbon-dioxide-to-gasoline factory: it requires a great deal of energy.
According to their analysis, their concept, which would cost about $5 billion to build, could produce gasoline at an operating cost of $1.40 a gallon and would turn economically practical when the price at the pump hits $4.60 a gallon.
Other scientists said the Los Alamos proposal perhaps looked promising but could not evaluate it fully because the details had not been published.
“It’s definitely worth pursuing,” said Martin I. Hoffert, a professor of physics at New York University. “It’s not that new an idea. It has a couple of pieces to it that are interesting.”
67. What is the idea of the project being discussed in the article?
A. Recycling the carbon dioxide from cars back into gasoline.
B. Create a new gasoline that gives off very little carbon dioxide.
C. Using a special liquid solution to absorb carbon dioxide from cars.
D. Build synthetic fuel factories to remove carbon dioxide from the air.
68. What’s the name given to the new concept?
A. Synthetic Fuel.                                B. Green Freedom.    
C. Renewable Fuel.                               D. Carbon-dioxide-to-gasoline Factory.
69. Which of the following is NOT one of the benefits of this new concept as suggested in the article?
A. Reduction of global warming.           B. Cheaper gasoline for cars.
C. Longer life of cars.                    C. Less pollution of the atmosphere.
70. What’s the biggest problem in realizing the concept according to the report?
A. Shortage of starting funds.        B. Immature technology involved.
C. All previous similar attempts have failed.
D. The use of too much energy in running the fuel factory.ABCD