题目

 “May I take your order now?” “We’d like three black _______ and two green _______.” A. coffee, cups of teas   B. coffees, teas C. cups of coffee, tea     D. cup of coffees, teas 答案：B向K2SO4和FeCl3的混合液中，滴入Ba(OH)2溶液，当完全沉淀时，Fe3+也同时被完全沉淀，则原混合溶液中K2SO4和FeCl3的物质的量浓度比为 [　　] A．3∶1B．3∶2 C．2∶1D．2∶3