单项选择题__________ A) The sea level will be 20 centimeters higher than it is now. B) The sea will be empty if we continue fishing at this pacE.C) The problems to explore the sea will have been largely solveD.D) People will depend largely on sea foods and minerals.
多项选择题虹吸式屋面雨水收集系统与半有压屋面雨水收集系统相比,其优势主要表现在( )。 A、悬吊管无需坡度敷设,节省安装空间 B、需要较大的管径 C、管道具有自洁能力 D、使用寿命更长 E、需要较小的管径