题目

The hurricane damaged many houses and business buildings；_________，it caused 20 deaths. A．or else              B．therefore        C．after all     D．besides 答案：D某水库大坝的横断面为梯形，坝顶宽6米，坝高24米，斜坡AB的坡角为45°，斜坡CD的坡度为1：2，则坝底AD的长为A.72米B.68米C.42米D.78米