Q23: GWD-2-Q19: 没有搜出来，大家来讨论讨论啊。

true

Q23: GWD-2-Q19:
Sunflowers growing in pots were placed, with their roots submerged, in the pond contaminated with radioactive elements.  The sunflowers kept growing; in the process, they absorbed radioactive elements.  Within twelve days, 85 percent of the radioactive elements were removed from the water, which is no less than can be accomplished with the much more expensive conventional filtration techniques.  Scientists therefore propose using sunflowers for decontamination wherever there are radioactively contaminated ponds.
Which of the following, if true, points to a limitation on the applicability of the proposed method of decontamination?
A.    Some plants other than sunflowers can also remove radioactive elements from water.
B.    The water in many ponds contaminated with radioactive elements is so cold that it would kill sunflowers whose roots were submerged in it.
C.    Sunflowers that grow with their roots submerged in water grow less well than sunflowers growing under optimal conditions on dry land.
D.    Only species of sunflowers with large leaves can have their roots submerged in water and still keep growing.
E.    In ponds in which the circulation of the water is artificially increased, sunflowers absorb radioactive elements far faster than they do in other ponds.

我选D，答案B
我觉得题目问points to a limitation，而选项D说只有宽叶的sunflowers才有题目说的功能，那么不正好说出并不是所有的sunflowers
均具有那些功能，因此不就是最好的limitation么？

fiaoyaya

你看结论：Scientists therefore propose using sunflowers for decontamination wherever there are radioactively contaminated ponds.

结论强调的是wherever，而没有说using (whichever kind of) sunflowers。所以D不能削弱，因为如果只有宽叶的能起作用的话，那就只用宽叶的sunflowers就可以达到效果。

而B的削弱主要在于削弱了结论中的wherever。因为水冷sunflowers活不了，所以这种方法并不是在任何水池中都能起作用。

true

收到。
主要是觉得B说的太绝了。
而且文章也指出Within twelve days, 85 percent of the radioactive elements were removed from the water,
在BD之间磨蹭，结果还是选错了。

sunnylbs

那E错在哪里了呢？当时虽然蒙对了B，可是回过头来还是不明白E为什么错。。。

苏格拉无底

我的理解是按E来说，只能推理怎样的池塘能让sunflower吸收的更快，但并不会削弱这个方案的适用性。

sunnylbs

明白了，多谢啦！