The rain comes from the_______. 

在CaCO₃→CaO→Ca（OH）₂→NaOH的各步转化中，所属的基本反应类型不包括（    ）

诺贝尔文学奖获得者、中国作家莫言在瑞典学院发表文学演讲，主题为“讲故事的人”（storyteller），莫言讲了关于他母亲的故事。某校七（4）班的学生从莫言讲述的故事中摘录了以下几个片段，请你用所学的知识参与解读。

片段一：小时侯，觉得自己丑，母亲对我说：“儿子，你不丑。你不缺鼻子不缺眼，四肢健全，丑在哪里？”

片段二：见到多年前欺负过母亲的人，我心里十分痛恨，冲上去想找他报仇，母亲拉住了我，平静的对我说：“儿子，那个打我的人，与这个老人，并不是同一个人。”

片段三：小时候辍学后，独自在荒草滩上去放牧牛羊。当看到昔日的同学在校园里打打闹闹，我心中充满悲凉，深深地体会到一个人，哪怕是一个孩子，离开群体后的痛苦。

片段四：我母亲不识字，但对识字的人十分敬重。我们家生活困难，经常吃了上顿没下顿。但只要我对她提出买书买文具的要求，她总是会满足我。

    My mother is a teacher. On weekdays, she gives lessons at school and on Saturdays she works in clubs. On Sundays, she is still busy.

On Sunday morning, mum gets up at six. She cooks breakfast for us first. And then it's time for cleaning. After that, she has breakfast with father and me. At 9, she goes to buy food for lunch in the supermarket. She can have a short rest after lunch. In the afternoon, mum doesn't go out. She helps me with my lessons. She does some reading, too.

    Mother watches TV at about 7 when she finishes (完成) the housework. But at that time she is always tired and falls asleep (睡着) in the sofa sometimes.