PREP1-17没思路！

YuCongyun

Urban air contains more sulfur dioxide than does rural air, and plants in cities typically grow more slowly than do plants in rural areas.  In an experiment to see how much of the difference in growth is due to sulfur dioxide, classes in an urban and a rural school grew plants in greenhouses at their schools and filtered the greenhouse air to eliminate sulfur dioxide.  Plants in the urban greenhouse grew more slowly than those in the rural greenhouse.

Which of the following, if true, would it be most important to take into account in evaluating the result?

(A) The urban school was located in a part of the city in which levels of sulfur dioxide in the air were usually far lower than is typical for urban areas.

(B) At both schools, the plants in the greenhouses grew much more quickly than did plants planted outdoors in plots near the greenhouses.

(C) The urban class conducting the experiment was larger than the rural class conducting the experiment.

(D) Heavy vehicular traffic such as is found in cities constantly deposits grime on greenhouse windows, reducing the amount of light that reaches the plants inside.

(E) Because of the higher levels of sulfur dioxide in the air at the urban school, the air filters for the urban school's greenhouse were changed more frequently than were those at the rural school.

这题完全没思路阿，请帮忙解答！

按照（D）的说法，这道题明明是削弱题嘛，而不是evaluation。

[此贴子已经被作者于2009-3-25 20:08:44编辑过]

balabaladou7

可以看成一道解释题，等同于划线complete题吧。

YuCongyun

谢谢mm

Melodyyang90

这道题不能看成是complete解释题，因为它不是让你对一个差异现象进行解释。题目是评价题，说明选项的答案可以对原题起到支持OR反对的效果。所以D项，起到了削弱的作用，也是对原题的一种评价。评价了对于这个结果的造成，并不是因为有毒空气的原因，而是光照的原因。

zbna5

以下是引用Melodyyang90在2009-5-23 15:17:00的发言：
这道题不能看成是complete解释题，因为它不是让你对一个差异现象进行解释。题目是评价题，说明选项的答案可以对原题起到支持OR反对的效果。所以D项，起到了削弱的作用，也是对原题的一种评价。评价了对于这个结果的造成，并不是因为有毒空气的原因，而是光照的原因。

这个解释好...