题目

下列物质在盛有空气的集气瓶内燃烧，使集气瓶内的压强明显降低的是 A.硫            B.木炭      C.红磷      D.铁丝 答案：CYou hardly have meals in the restaurant, ________?A.have youB.haven't youC.don't youD.do you