题目

阅读理解；阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项。 You may never be in an emergency situation. But if it happens, you should know how to get help. The telephone book in the United States has emergency numbers on the inside front cover. Look at the following table from the Boston telephone book. Notice that the numbers for the police and the fire department (部门) are the same. And it is an easy number to remember. If you are too unhappy or excited to remember any numbers at all, you can simply dial (拨打) “0” for an operator (下列关于离子检验的说法中正确的是（　　）A. 向某溶液中加入AgNO3溶液，生成白色沉淀，该溶液中一定含有Cl－B. 向某溶液中加入稀盐酸，产生无色气体，则该溶液中一定含有COC. 向某溶液中加入NaOH溶液，用蓝色石蕊试纸检验逸出的气体，试纸变红，则该溶液中一定含有NH4+D. 向某溶液中加入2滴KSCN溶液，溶液不显红色，再向溶液中加几滴新制的氯水，溶液变为红色，则该溶液中一定含有Fe2＋