根据液体压强的特点及拦河坝的功能可知，拦河坝横截面的形状是图中的____________________(是甲？乙？丙？还是丁？）
热心网友
梯形，下宽上窄。没图，只好大概说一下形状了 ：）
热心网友
梯形，上窄下款
热心网友
失败，没有图我怎么答呀！不过是上宽下窄。
热心网友
没错，就是梯形，从水面到水下逐渐变宽，是为了适应逐渐增大的水压，保证大坝的安全和稳定性。
热心网友
上图正确
热心网友
应该是：`````_______``````````````````````````````````````_______````````````/```````\`````````````````水`````````````````/```````\```````````/``````````\```````````````水```````````````/``````````\``````````/`````````````\`````````````水`````````````/`````````````\`````````/````````````````\```````````水```````````/````````````````\````````/```````````````````\`````````水`````````/```````````````````\```````/``````````````````````\```````水```````/``````````````````````\``````/`````````````````````````\`````水`````/`````````````````````````\。