①干冰    ②氢氧化钙    ③甲烷  ④硝酸铵固体

【提出问题】这瓶溶液是什么溶液？

【获得信息】实验中用到含有钠元素的物质是氯化钠、氢氧化钠、碳酸钠

【提出猜想】这瓶溶液原来是：

猜想一：氯化钠溶液；   猜想二：氢氧化钠溶液；   猜想三：碳酸钠溶液．

【实验推断】

①甲取样滴加无色酚酞试液，溶液呈红色，得出结论：该溶液不可能是____溶液，理由是____．

②乙另取样滴加稀盐酸有____产生，乙得出结论：该溶液原来是碳酸钠溶液．

③丙认为乙的结论不完全正确，理由是____．小组同学讨论后一致认为还需要进行如下实验：

【继续探究】④另取样加入过量的氯化钙溶液，观察到有____产生，设计这一步骤的目的是；静置后，取上层清液，滴入酚酞试液，溶液呈红色．

【得出结论】⑤这瓶溶液原来是____

【拓展迁移】⑥氢氧化钠溶液与盐酸发生中和反应，恰好完全反应的微观过程如图2所示，反应的实质表达式为：H⁺+OH^﹣=H₂O，则反应后溶液中存在的阴、阳离子是____（填离子符号）；请写出【继续探究】实验中加氯化钙溶液反应的实质表达式：____（仿照上例，用离子符号表示）

   A pretty, well-dressed young lady stopped a taxi in a big square, and said to the driver, “Can you see that young man at the other side of the square?”
   “Yes,” said the taxi-driver. The young man was standing outside a restaurant and looking impatiently at his watch every few seconds.
   “Take me over there.” said the young lady.
   There were a lot of cars and buses and trucks in the square, so the taxi- driver asked, “Are you afraid to cross the street.”
   ‘Oh, no !” said the young lady. “But I said that I would meet that young man for dinner at one o’c1ock, and it is now a quarter to two. If I arrive in a taxi, it will at least seem as if I have tried not to be too late.”