题目

It was about 5 o’clock in the afternoon _______ they had their supper. A. that             B. what             C. before           D. when 答案：D 解析: 略下列各组物质在水溶液中能大量共存，且能形成无色溶液的是（　　）A. CuSO4 H2SO4B. NaNO3 KClC. HCl Na2CO3D. H2SO4 Ba(NO3)2