题目

 ---Come on! I know you are not satisfied with the results. You must have a lot to complain ______ your partner John.  ---No! I really have nothing ______ him.     A. with; against        B. of; with             C. about; with      D. about; against 答案：D室温下，下列物质的水溶液，其pH小于7的是（　　）A．Na2CO3B．NH4ClC．Na2SO4D．KNO3