GRE Reading Comprehension: JiJing 352-GRE阅读机经352篇 - UU4R052KXY43PHVSJ

Which of the following would be most useful to determine the possibility that the grapes yields increase with the raise of the temperature? A. Whether increasing carbon dioxide levels in greenhouses improves the eating quality of the grapes grown in the greenhouses B. Whether in the future the market for grapes will be greater than it is now C. Whether temperatures today often get so high in regions where grapes are grown that the grapes suffer serious damage D. Whether the use of greenhouses for growing grapes serves research purposes only E. Whether the economic benefits that might be derived from a major increase in world grape production would outweigh any economic harm resulting from negative health effects associated with increased worldwide carbon dioxide levels