一道prep题，帮忙看看啊！

maggie1121

102.


In parts of South America, vitamin-A deficiency is a serious health problem, especially among children.In one region, agriculturists hope to improve nutrition by encouraging farmers to plant a new variety of sweet potato called SPK004 that is rich in betacarotene, which the body converts into vitamin A.The plan has good chances of success, since sweet potato is a staple of the region’s diet and agriculture, and the varieties currently grown contain little beta-carotene.

Which of the following, if true, most strongly supports the prediction that the plan will succeed?

A. There are other vegetables currently grown in the region that contain more beta-carotene than the currently cultivated varieties of sweet potato do.

B. The flesh of SPK004 differs from that of the currently cultivated sweet potatoes in color and texture, so traditional foods would look somewhat different when prepared from SPK004.

C. For successful cultivation of SPK004, a soil significantly richer in nitrogen is needed than is needed for the varieties of sweet potato currently cultivated in the region.

D.There are no other varieties of sweet potato that are significantly richer in beta-carotene than SPK004 is.

E. The currently cultivated varieties of sweet potato contain no important nutrients that SPK004 lacks.

正确答案是E，但我还是不大明白，觉得很牵强，求NN帮忙解释一下，还有如何排除D选项呢？谢谢~~

peter3008

我是这么做这题的：（确实做完之后不是很确定，但是还是对了）
先读题目：措施达目的 类型， 措施具有可行性可以到达目的
提干：目的： to improve nutrition 措施：plant SPK004
推出结论的前提：since sweet potato is a staple of the region’s diet and agriculture, and the varieties currently grown contain little beta-carotene.

我是用排除法作的，因为读了一遍选项，没有感觉。结论是 plant spk004能够提高nutrition. 加强的是，spk400跟别的同类比能够提高nutrition.

A.说的other vegetables
B.说的color and texture, so traditional foods
C.richer in nitrogen的多少
D.other varieties of sweet potato that are significantly richer in beta-carotene than SPK004 is.

我就想中间的假设，当然啦，最重要的假设有2个: spk004要种的成功 ( 生长条件要跟别的一样才能在这里种的活），spk004也要有跟别的有一样的营养，不然光光vita A高就没有用了。

排除下来，C,D,E需要考虑，

C只是陈述了spk需要的条件，可是文中并没有说那个地区的nitrogen多还是少，够不够生长，对于原文并没有起到任何作用

D我自己是首先排除的，为什么呢？因为这个选项只是简单的重复了文中的条件，SPK004 that is rich in betacarotene & varieties currently grown contain little beta-carotene 并没有起到什么加强。

E.如果spk004跟别的同类东东都一样，再加上vita A更高，是不是就加强了 to  improve nutrition 的目的，原本提供的营养不变的基础上再加上更多的vita A，多好的一个假设阿!

当然，实战的时候想不了那么多，差不多对了就要选了，不可能做这样的分析，除非你的阅读能力，逻辑能力真的是很强

maggie1121

D和E都不是直接说SPK004，但都是与其相关的比较。为了说明SPK4能succeed，D项突出没有比它含胡萝卜素量更高的土豆变种，不正是加强的说法吗！E项没有说出SPK的优点，反而lack某些重要的营养物，而且原句说的是现行土豆也没有，所以总体看来，E没有起到加强SPK的作用。
大家觉得是不是这样的呢？

mudiduange

D是无关选项，原文探讨的是SPK004是否是一个好的选择，那么选项只要回答这个问题即可，不用去关心其他的种类的土豆