D is in fact a strengthener of the original argument, which claims that major eruptions cause the atmosphere to become cooler than it would be otherwise. It simply provides a reason to explain how an erruption can stop the general WARMING trend for a brief time. So D is not a weakener for the question. -- by 会员 sdcar2010 (2011/3/28 21:27:25)
Why a strenghener? Personally,D is correct as well. Stimulus:eruptions-->severe winter D:The climatic effects of major volcanic eruptions mask the general warming(as an another reason)-->severe winter Therefore,I can accept D. Please correct me! |