题目

任务型阅读：（10分）Almost everyone likes dogs, and almost everyone likes reading stories about dogs.I have a friend. (1)The friend has a large police dog. Its name is Jack. Police dogs are very clever. Every Sunday afternoon my friend takes Jack for a long walk in the park, Jack likes these long walks very much.One Sunday afternoon a young man came to visit my friend. He stayed for a long time. He talked and talked. Soon it was time for my friend to take Jack for his walk. But the visitor still stayed. Jack became very worried. He walked around the room several times and then sat dow现有H2SO4、BaCl2、Na2CO3、NaNO3四种物质的溶液，要求只用一种试剂将这四种物质的溶液逐步区别开来．下列试剂中不可能达到目的是（　　）A．石蕊试液B．NaCl溶液C．稀盐酸D．Ba（OH）2溶液