[求助]实在太散了,我只好直接请教5道prep逻辑

做GWD的时候还觉得BF题很简单,怎么做了PREP就错误率很高,对选项意思也不是很了解...就考试了,有点急

先感谢大家了!

27.   (31231-!-item-!-188;#058&004411)

Plant scientists have used genetic engineering on seeds to produce crop plants that are highly resistant to insect damage.  Unfortunately, the seeds themselves are quite expensive, and the plants require more fertilizer and water to grow well than normal ones.  Thus, for most farmers the savings on pesticides would not compensate for the higher seed costs and the cost of additional fertilizer.  However, since consumer demand for grains, fruits, and vegetables grown without the use of pesticides continues to rise, the use of genetically engineered seeds of this kind is likely to become widespread.

In the argument given, the two portions in boldface play which of the following roles?

(A) The first supplies a context for the argument; the second is the argument's main conclusion.

(B) The first introduces a development that the argument predicts will have a certain outcome; the second is a state of affairs that the argument denies will be part of that outcome.

(C) The first presents a development that the argument predicts will have a certain outcome; the second acknowledges a consideration that weighs against that prediction.

(D) The first provides evidence to support a prediction that the argument seeks to defend; the second is that prediction.

(E) The first and the second each provide evidence to support the argument's main conclusion.

Some airlines allegedly reduce fares on certain routes to a level at which they lose money, in order to drive competitors off those routes.  However, this method of eliminating competition cannot be profitable in the long run.  Once an airline successfully implements this method, any attempt to recoup the earlier losses by charging high fares on that route for an extended period would only provide competitors with a better opportunity to undercut the airline's fares.

Which of the following, if true, most seriously weakens the argument?

(A) In some countries it is not illegal for a company to drive away competitors by selling a product below cost.

(B) Airline executives generally believe that a company that once underpriced its fares to drive away competitors is very likely to do so again if new competitors emerge.

(C) As part of promotions designed to attract new customers, airlines sometimes reduce their ticket prices to below an economically sustainable level.

(D) On deciding to stop serving particular routes, most airlines shift resources to other routes rather than reduce the size of their operations.

(E) When airlines dramatically reduce their fares on a particular route, the total number of air passengers on that route increases greatly.

这道有没有点诉诸权威的意思??

17.   (26864-!-item-!-188;#058&003368)

At present the Hollywood Restaurant has only standard-height tables.  However, many customers come to watch the celebrities who frequent the Hollywood, and they would prefer tall tables with stools because such seating would afford a better view of the celebrities.  Moreover, diners seated on stools typically do not stay as long as diners seated at standard-height tables.  Therefore, if the Hollywood replaced some of its seating with high tables and stools, its profits would increase.

The argument is vulnerable to criticism on the grounds that it gives reason to believe that it is likely that

(A) some celebrities come to the Hollywood to be seen, and so might choose to sit at the tall tables if they were available

(B) the price of meals ordered by celebrities dining at the Hollywood compensates for the longer time, if any, they spend lingering over their meals

(C) a customer of the Hollywood who would choose to sit at a tall table would be an exception to the generalization about lingering

(D) a restaurant's customers who spend less time at their meals typically order less expensive meals than those who remain at their meals longer

(E) with enough tall tables to accommodate all the Hollywood's customers interested in such seating, there would be no view except of other tall tables

20.   (27836-!-item-!-188;#058&003666)

During the past year, Pro-Tect Insurance Company's total payout on car-theft claims has been larger than the company can afford to sustain.  Pro-Tect cannot reduce the number of car-theft policies it carries, so it cannot protect itself against continued large payouts that way.  Therefore, Pro-Tect has decided to offer a discount to holders of car-theft policies whose cars have antitheft devices.  Many policyholders will respond to the discount by installing such devices, since the amount of the discount will within two years typically more than cover the cost of installation.  Thus, because cars with antitheft devices are rarely stolen, Pro-Tect's plan is likely to reduce its annual payouts.

In the argument above, the two portions in boldface play which of the following roles?

(A) The first and the second are both evidence offered by the argument as support for its main conclusion.

(B) The first presents a problem a response to which the argument assesses; the second is the judgment reached by that assessment.

(C) The first is the position the argument seeks to establish; the second is a judgment the argument uses to support that position.

(D) The first is a development that the argument seeks to explain; the second is a prediction the argument makes in support of the explanation it offers.

(E) The first presents a development whose likely outcome is at issue in the argument; the second is a judgment the argument uses in support of its conclusion about that outcome.

23.   (28303-!-item-!-188;#058&003943)

A product that represents a clear technological advance over competing products can generally command a high price. Because technological advances tend to be quickly surpassed and companies want to make large profits while they still can, many companies charge the maximum possible price for such a product.  But large profits on the new product will give competitors a strong incentive to quickly match the new product's capabilities.  Consequently, the strategy to maximize overall profit from a new product is to charge less than the greatest possible price.

In the argument above, the two portions in boldface play which of the following roles?

(A) The first is a consideration that has been raised to argue that a certain strategy is counterproductive; the second presents that strategy.

(B) The first is a consideration raised to support the strategy that the argument recommends; the second presents that strategy.

(C) The first is a consideration raised to explain the appeal of a certain strategy; the second presents that strategy.

(D) The first is an assumption, rejected by the argument, that has been used to justify a course of action; the second presents that course of action.

(E) The first is a consideration that has been used to justify pursuing a goal that the argument rejects; the second presents a course of action that has been adopted in pursuit of that goal.