[求助]两道补充材料的逻辑。感谢感谢~~

Damaged nerves in the spinal cord do not regenerate
  themselves naturally, nor even under the spur of
  nerve-growth stimulants. The reason, recently dis-
  covered, is the presence of nerve-growth inhibitors
  in the spinal cord. Antibodies that deactivate those
  inhibitors have now been developed. Clearly, then,
  nerve repair will be a standard medical procedure in
  the foreseeable future.

  Which of the following, if true, casts the most serious
  doubt on the accuracy of the prediction above?
  (A) Prevention of the regeneration of damaged
      nerves is merely a by-product of the main
      function in the human body of the substances
      inhibiting nerve growth.
  (B) Certain nerve-growth stimulants have similar
      chemical structures to those of the antibodies
      against nerve-growth inhibitors.
  (C) Nerves in the brain are similar to nerves in the
      spinal cord in their inability to regenerate
      themselves naturally.
  (D) Researchers have been able to stimulate the
      growth of nerves not located in the spinal cord
      by using only nerve-growth stimulants.
  (E) Deactivating the substances inhibiting nerve
      growth for an extended period would require a
      steady supply of antibodies.

想问问是怎么削弱的 是副产物能说明什么呢？

Over the last century, paleontologists have used
   small differences between fossil specimens to
   classify triceratops into sixteen species. This
   classification is unjustified, however, since the
   specimens used to distinguish eleven of the species
   come from animals that lived in the same area at
   the same time.

   Which of the following, if true, would enable the
   conclusion of the argument to be properly drawn?
   (A) Not every species that lived in a given area is
       preserved as a fossil.
   (B) At least one individual of every true species of
       triceratops has been discovered as a fossil
       specimen.
   (C) No geographical area ever supports more than
       three similar species at the same time.
   (D) In many species, individuals display quite
       marked variation.
   (E) Differences between fossil specimens of tri-
       ceratops that came from the same area are no
       less distinctive than differences between
       specimens that came from different areas.

看不懂题目再说什么，更别说“逻辑”了。

郁闷死了！！！救命啊！！！

刚给riceGG敲了一半,突然没了,唉,苦啊~~~~

1.inhibitors阻碍了受损神经元的修复, 题目中提出使用一种stimulant可以把inhibitors被desactivate掉,还建议讲这种做法使用到医学上去.

A指出阻碍神经元修复只是这种inhibors在人体内所发挥功能的极小部分, 那么如果被desactivate掉, inhibitors本来发挥的一些主要的有益的功能也没了,所以削弱

2.题目说考古学家运用化石样本中的微小差异界定出6种species, 认为这种分类是不合理的,因为样本来自在同一时间/,生活在同一地区的动物,问assumption,即要在原因和结果间建立联系,所以是C,在同意时间内,任何地域都不可能出现三种以上类似的species

谢谢marie，第一题明白了。

第二题是因为没看懂题目。不过觉得思路好奇怪。题目中的conclusion是this classification is unjustified是吧. 要找一个“支持”的。说一个地区不可能出现3个以上species.  所以那16个species的分类就更不可能了。于是就支持了。是这样么？

感觉自己做了逻辑以后自己的思路跟ets特别不一样：（  得使劲往上面靠：（（

很正确!

thanks rice. what is ftp?  can I get e file then?

XDF only sell three items for GMAT Wang luo ke tang ( OG, jiang yi and Yu's Si Hui.)  XDF does not sell GMAT Bu chong CAi liao.