大全-10-8. For the safety-conscious Swedish market, a United States manufacturer of desktop computers developed a special display screen that produces a much weaker electromagnetic field surrounding the user than do ordinary screens. Despite an advantage in this respect over its competitors, the manufacturer is introducing the screen into the United States market without advertising it as a safety improvement.

Which of the following, if true, provides a rationale for the manufacturer’s approach to advertising the screen in the United States?

(A) Many more desktop computers are sold each year in the United States market than are sold in the Swedish market.

(B) The manufacturer does not want its competitors to become aware of the means by which the company has achieved this advance in technology.

(C) Most business and scientific purchasers of desktop computers expect to replace such equipment eventually as better technology becomes available on the market.

(D) An emphasis on the comparative safety of the new screen would call into question the safety of the many screens the manufacturer has already sold in the United States.（D）

(E) Concern has been expressed in the United States over the health effects of the large electromagnetic fields surrounding electric power lines.

答案是D，这个明白。但是，b好象也对。advertising the screen有可能或在一定程度上会competitor become aware of technology。

题目要求Rationale的解释，对于这类题，有些可能的选项不考虑？

原文不是说没有作广告，而是不将它广告成一项技术改进。

B错的原因是没有任何信息支持不广告是不让对手知道其技术领先这一推理。原文focus在不广告为安全改进。B没有针对这个focus。

D正确因为广告这一点会危及它以前生产的显示器。所以说明了原文的结论不将其广告为安全改进的理由。

谢谢

我还是有下面的疑问的：

1、并不是没有任何信息支持不广告是不让对手知道其技术领先。manufacturer可能有这样的想法：为了不让对手知道，就不将它广告成一项技术改进。

而且，文中陈述的是事实：The manufacturer does not want its competitors to become aware of the technology.说明manufacturer 确实有这种想法，并且合情合理。这就解释了他们为什么不将它广告成一项技术改进。

2、同意原文focus在不广告为安全改进。但是B确实针对这个focus了：不广告为安全改进的原因就是不让对手知道其技术领先。

大家都帮着看看。

The expansion of large-scale farming in Africa and Asia has destroyed much of the natural vegetation on which elephants have historically depended, forcing them to turn to cultivated land to satisfy their enormous appetites. As a result, farmers have lost millions of dollars worth of crops annually. Yet even if elephant sanctuaries were created on a widespread basis to guarantee elephants sufficient natural vegetation, the raiding would likely persist, since

(A) when elephants forage for food, they typically travel in herds.

(B) foraging elephants have been known to cause substantial damage even to plants that they do not eat.

(C) some of the land where crops have suffered extensive damage from elephants has been allowed to return to its natural state.

(D) elephants tend to prefer cultivated crops to wild vegetation as a food source

(E) elephant sanctuaries are usually created in areas that are rich in the natural vegetation on which elephants have historically depended.(D)