Q33:

Crowding on Mooreville’s subway frequently leads to delays, because it is difficult for passengers to exit from the trains. Subway ridership is projected to increase by 20 percent over the next 10 years. The Metroville Transit Authority plans to increase the number of daily train trips by only 5 percent over the same period. Officials predict that this increase is sufficient to ensure that the incidence of delays due to crowding does not increase.

Which of the following, if true, provides the strongest grounds for the officials’ prediction?

1. By changing maintenance schedules, the Transit Authority can achieve the 5 percent increase in train trips without purchasing any new subway cars.
2. The Transit Authority also plans a 5 percent increase in the number of bus trips on routes that connect to subways.
3. For most commuters who use the subway system, there is no practical alternative public transportation available.
4. Most of the projected increase in ridership is expected to occur in off-peak hours when trains are now sparsely used.
5. The 5 percent increase in the number of train trips can be achieved without an equal increase in Transit Authority operational costs.

答案是D。虽然选对了，但是用的排除法，对整个思路还不清楚，谁能解释一下吗？谢谢！

To answer this question, one has to look at each individual answer choices as you did. Since you can already eliminate the other choices, D is left as the best answer :-)

Why is D the best answer? If D is true, "Most of the projected increase in ridership is expected to occur in off-peak hours when trains are sparsely used", then obviously the increase in ridership won't cause more crowding, which means the need for increased train trips is smaller -- the officials' prediction is supported.