一道PREP的逻辑题 烦请大家帮忙解答下 谢谢

wjk

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.
答案：D
这道题目我当时没选D，因为题目中说是因为s d这个东西导致城市和郊区植物生长产生差异的原因，觉得D类似于是一个无关选项 后来看了下题目中说，是不是在做实验时过滤掉s d这个成分，保证在城市和郊区greenhouse中的空气质量一样，然后因为城市空气差，使床上覆盖了一层东西，影响了光的进入，才影响城市中植物的生长？ 是这么理解吗？

雪梦儿

是的，光合作用嘛~我也做错了，一开始。。。

cutie0829

头像不错