[求助]请教削弱结论和削弱论据的区别？

我在做题的时候经常为不知道怎么WEAKEN ARGUMENT 而头疼，不知道去针对那句话去削弱，请教如何去做WEAKEN ARGUMENT的 QUESTIONS？  这两方有什么区别呢？

多谢。

Questions 119 – 120 are based on the following.

According to the Tristate Transportation Authority, making certain improvements to the main commuter rail line would increase ridership dramatically. The authority plans to finance these improvements over the course of five years by raising automobile tolls on the two high-way bridges along the route the rail line serves. Although the proposed improvements are indeed needed, the authority’s plan for securing the necessary funds should be rejected because it would unfairly force drivers to absorb the entire cost of something from which they receive no benefit.

120.

Which of the following, if true, would provide the authority with the strongest counter to the objection that its plan is unfair?

(A) Even with the proposed toll increase, the average bridge toll in the tristate region would remain less than the tolls charged in neighboring states.

(B) Any attempt to finance the improvements by raising rail fares would result in a decrease in ridership and so would be self-defeating.

(C) Automobile commuters benefit from well-maintained bridges, and in the tristate region bridge maintenance is funded out of general income tax revenues to which both automobile and rail commuters contribute.

(D) The roads along the route served by the rail line are highly congested and drivers benefit when commuters are diverted from congested roadways to mass transit.

(E) The only alternative way of funding the proposed improvements now being considered is through a regional income tax surcharge, which would affect automobile commuters and rail commuters alike.

答案

OG104.

Spending on research and development by United States businesses for 1984 showed an increase of about 8 percent over the 1983 level. This increase actually continued a downward trend evident since 1981 – when outlays for research and development increased 16.4 percent over 1980 spending. Clearly, the 25 percent tax credit enacted by Congress in 1981, which was intended to promote spending on research and development, did little or nothing to stimulate such spending.

The conclusion of the argument above cannot be true unless which of the following is true?

(A) Business spending on research and development is usually directly proportional to business profits.

(B) Business spending for research and development in 1985 could not increase by more than 8.3%.

(C) Had the 1981 tax credit been set higher than 25%, business spending for research and development after 1981 would have increased more than it did.

(D) In the absence of the 25% tax credit, business spending for research and development after 1981 would not have been substantially lower than it was.

(E) Tax credits market for specific investments are rarely effective in inducing businesses to make those investments.

答案