题目

在某无色透明溶液中，能大量共存的离子组是( ) A．K＋、MnO4—、SO42—                      B．Al3＋、Cl—、SO42— C．Na＋、CH3COO—、H＋                     D．OH—、Na＋、Fe3＋ 答案：B---Here's a new pair of shoes for you. 　　----Thank you, but there's no need ______ a new pair for me. 　　A. to have bought     　B. to buy     　　C. buying   　　D. to be buying