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Which of the following most logically completes the argument?? When people engage in activities that help others ,their brain releases endorphins, the brain’s natural opiates, which induce in people a feeling of well-being. It has been suggested that regular release of endorphins increases people’s longevity. And a statistic on adults who regularly engage in volunteer work helping others shows that they live longer, on average, than adults who do not volunteer. How- ever, that statistic would be what we would expect even if volunteering does not boost longevity, because . A. in the communities studied, women were much more likely to do regular volunteer work than men were, and women tend to live longer than men do. B. the number of young adults who do regular volunteer work is on the increase C. the feelings of well-being induced by endorphins can, at least for a time, mask the symptoms of various conditions and diseases, provided the symptoms are mild. D. it is rare for a person to keep up a regular schedule of volunteer work through- out his or her life. E. Some people find that keeping a commitment to do regular volunteer work becomes a source of stress in their lives. ============================================================= Yeasts capable of leavening bread are widespread, and in the many centuries during which the ancient Egyptians made only unleavened bread, such yeasts must frequently have been mixed into bread doughs accidentally. The Egyptians, however, did not discover leavened bread until about 3000 B. C. That discovery roughly coincided with the introduction of a wheat variety that was preferable to previous varieties because its edible kernel could be removed from the husk without first toasting the grain.
Which of the following, if true, provides the strongest evidence that the two developments were causally related? A. Even after the ancient Egyptians discovered leavened bread and the techniques for reliably producing it were well known, unleavened bread continued to be widely consumed. B. Only when the Egyptians stopped the practice grain were their stone- lined grain-toasting pits available for baking bread. C. Heating a wheat kernel destroys its gluten, a protein that must be present in order for yeast to leaven bread dough. D. The new variety of wheat, which had a more delicate flavor because it was not toasted, was reserved for the consumption of high officials when it first began to be grown. E. Because the husk of the new variety of wheat was more easily removed, flour Made from it required less effort to produce. =========================================================== 能麻烦大家给我解释下吗~？谢谢了啊！！！~~~~ | 
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发表于 2009-10-28 14:25:00
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