13. Five years ago, during the first North American outbreak of the cattle disease CXC, the death rate from the disease was 5 percent of all reported cases, whereas today the corresponding figure is over 18 percent. It is clear, therefore, that during these past 5 years, CXC has increased in virulence.
Which one of the following, if true, most substantially weakens the argument?
(A) Many recent cattle deaths that have actually been caused by CXC have been mistakenly attributed to another disease that mimics the symptoms of CXC.
(B) During the first North American outbreak of the disease, many of the deaths reported to have been caused by CXC were actually due to other causes.
(C) An inoculation program against CXC was recently begun after controlled studies snowed inoculation to be 70 percent effective in preventing serious cases of the illness.
(D) Since the first outbreak, farmers have learned to treat mild cases of CXC and no longer report them to veterinarians or authorities.
(E) Cattle that have contracted and survived CXC rarely contract the disease a second time.
我的问题答案是d，它是如何削弱的？？？
23. Mayor Smith, one of our few government officials with a record of outspoken, informed, and consistent opposition to nuclear power plant construction projects, has now declared herself in favor of building the nuclear power plant at Littletown. If someone with her past antinuclear record now favors building this power plant, then there is good reason to believe that it will be safe and therefore should be built.
The argument is vulnerable to criticism on which one of the following grounds?
(A) It overlooks the possibility that not all those who fail to speak out on issues of nuclear power are necessarily opposed to it.
(B) It assumes without warrant that the qualities enabling a person to be elected to public office confer on that person a grasp of the scientific principles on which technical decisions are based.
(C) It fails to establish that a consistent and outspoken opposition is necessarily an informed opposition.
(D) It leads to the further but unacceptable conclusion that any project favored by Mayor Smith should be sanctioned simply on the basis of her having spoken out in favor of it.
(E) It gives no indication of either the basis of Mayor Smith’s former opposition to nuclear power plant construction or the reasons for her support for the Littletown project.
1. premises: 18%death among REPORTED CXC cases, in contrast to 5% during the first outbreak; conclusion:CXC毒性增强 D weaken. 因为很多农民自己料理了,根本就没report --> 统计的基数小了 -->18%不是因为毒性大.
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2003-4-14 22:58:00
楼主