Passage 186 一道阅读jj里的逻辑题求解答

啊GRE好难

Passage 186

Growing grapes in greenhouses containing air enriched with carbon dioxide increases cropyields, an effect that is enhanced when the growing temperature is also raised severaldegrees. Although enclosed cultivation is impractical in vineyards, increases in yields fromgrape cultivation in the open can be expected because emissions from the burning of fossilfuels will almost certainly lead to an increase in the carbon dioxide content of atmospheric airover the next century.

1. Which of the following, if true, most weakens the argument?
A. When grapes are grown in greenhouses, it is relatively easy to control the grape pests thatthrive in air enriched with carbon dioxide.
B. Recent improvements in pest control have increased grape yields in many vineyards.
C. Increasing carbon dioxide levels in greenhouses has not been shown to improve the qualityof grapes grown in greenhouses.
D. Increasing carbon dioxide levels in greenhouses increases the sweetness of raisins madefrom grapes grown in the greenhouses.
E. As the carbon dioxide level in the open air increases, temperatures at the Earth's surfacewill also increase


答案是A，想问下为什么不能选B呀～B算他因吗？我的思路是：因为pest control improvement 可以增加grape yields, 所以不能代表grape yield 增加是因为open air
                                       
                                
                        
               

dada715

题目论证梳理了一下，发现是 greenhouse vs open 的差别，推断二者不同结果 是 因为二氧化碳量不同

为了推翻这个说法
A.就说了 greenhouse里是pest好控制，所以收成号

B.说了pest control improvement，但是没说室内室外，那就缺少信息了，没法判断，