题目

There has been ____ accidents on this part of road. A. a number of                    B. a great deal of C. a series of                       D. plenty of 答案：C 解析: 略0.5L 1mol/L FeCl3溶液中的Cl-的物质的量是（ ）A．3molB．1.5molC．1molD．0.5mol