og-23题目 A cost-effective solution to the problem of airport congestion is to provide high-speed ground transportation between major cities lying 200 to 500 miles apart. The successful implementation of this plan would cost far less than expanding existing airports and would also reduce the number of airplanes clogging both airports and airways.

Which of the following, if true, could be proponents of the plan above most appropriately cite as a piece of evidence for the soundness of their plan?

A. An effective high-speed ground-transportation system would require major repairs to many highways and mass-transit improvements B. One-half of all departing flights in the nation’s busiest airport head for a destination in a major city 225 miles away. C. The majority of travelers departing from rural airports are flying to destinations in cities over 600 miles away. D. Many new airports are being built in areas that are presently served by high-speed ground-transportation systems. E. A large proportion of air travelers are vacationers who are taking long-distance flights. 解释： The plan proposes that high-speed ground transportation would be a less expensive solution to airport congestion than would airport expansion. B indicates that between the cities to be served by the plan there is substantial air travel to which ground transportation would represent an alternative. Therefore, B is the best answer.

No other choice could be cited appropriately. A and D both provide some evidence against the plan. A by emphasizing the likely costs of providing high-speed ground transportation is not by itself a solution to airport congestion. D by indicating that such an alternative is not by itself a solution to airport congestion. C and E say that there are many travelers for whom the proposed system would actually provide no alternative.

疑问：解释中说A and D both provide some evidence against the plan。然后解释D by indicating that such an alternative is not by itself a solution to airport congestion。不能理解如何jD选项是如何against the plan.

在D中可以看到，说在有机场的地方已经有高速公路了，也就是说虽有高速公路系统，但是这个高速公路系统也并没有解决堵塞的问题，所以是against the plan.