LSAT-9-1-13

winsx2008

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 showed 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.（D）

(E) Cattle that have contracted and survived CXC rarely contract the disease a second time.

   我觉得a也对呀。a说由于现在的18%是因为有许多不是cxc引起的。而是与cxc类似的引起的 。所以毒性并没有增强。也削弱了结论呀

danggichen

你好想是把题目看反了吧，（A）是说很多最近牛的死亡实际上是由CXC引起的，只是由于和另一种病的病症很像，所以被误归为另一种病了

我一次也看反了，你再看看啊：）

winsx2008

    看错了！

c_violet2000

我想不通答案为什么是Ｄ．农民不再报告病列，不是应该减少百分比吗？怎么会增加呢？求助求助！

mygoalusa

Yes, you are on the right track, the goal of weakening the argument is to show that CXC has not increaed in virulence but decreased, just as you said.