根据短文内容和所给的首字母，写出短文中所缺的单词，使短文完整，合乎情景。

       The mobile phone is a useful thing, but maybe I don't know h    1      to use it. Sometimes it makes things

difficult for me.

       One day I wanted to see my friend nearby. I could a    2     at his house in five minutes, but I looked at my

mobile phone and thought i     3     would be better to ring him up. I r    4     him for the first time, but the line

was busy. Five minutes later, there was an answer, but it was the wrong number. Then I tried a    5    and this

time I got an answer from him.

       I asked him i    6    he was at home in the afternoon. And he said he would be at home all afternoon. So

I went to his house, but then I found n    7     in. I called him for the fourth time. This time I got so angry that

I s     8     , "You are not at home? But you just told me over the telephone that you would be at home all

afternoon!"

       Here w    9     his answer, "No, I said: 'I will NOT be at home all afternoon.' "I went back to my room,

sat down in front of the mobile phone and looked at it. What e    10     could I do? Nothing!

某化工厂用石灰石（杂质不溶于水，也不参加反应）、纯碱和水等原料来制烧碱溶液，再经过滤、蒸发等步骤制取固体烧碱。某化学兴趣小组要分析该化工厂仓库中放置一段时间后的固体烧碱样品成分，他们对烧碱样品的成分进行了如下猜测：

（1）【猜想】

猜想一：该样品的成分可能只有氢氧化钠；

猜想二：该样品中除了氢氧化钠外，还可能含有碳酸钠。支持这种猜测的依据是（用化学方程式表示）。                                                                    

猜想三：该样品中除了氢氧化钠外，还可能有氢氧化钙和碳酸钙。

猜想四：该样品中除了氢氧化钠外，还可能有氢氧化钙和碳酸钠

（2）【实验与验证】他们设计实验进行探究，

首先验证猜想一。进行的实验是：取少量固体样品配制成溶液，将少量溶液加入试管中，滴入酚酞，观察到试液变红。由此得出的结论是该样品只有氢氧化钠。他们又反思实验过程，觉得结论不正确，理由是                                                 。

他们验证猜想二，请你帮助完成实验表格。

（3）【反思与评价】通过验证猜想二中的实验，他们认为猜想三和猜想四都不能成立。请你分析理由                                                   。